Empirical support for "The Great Porn Experiment" - TEDx Glasgow (2012): Page 2

Printer-friendly version

Introduction

This page, and a second page, provide empirical support for claims put forth in The Great Porn Experiment | Gary Wilson | TEDxGlasgow. Each PowerPoint slide and associated text is accompanied by (1) the original supporting citations/sources, followed by (2) supporting studies and clinical evidence published in the intervening years. Slides 18 through 35 are below. The first page contains slides 1 through 17.

It’s important to note that The Great Porn Experiment was completed and sent to TEDx in December 2011, while the talk was given in March, 2012. This TEDx talk was a direct response to Philip Zimbardo's "Demise of Guys" TED talk, which the Glasgow audience viewed just prior to the talk.

Since December 2011, a large body of supporting research and clinical evidence has arrived to support The Great Porn Experiment's three primary assertions, which were:

  1. Internet porn can cause sexual dysfunctions;
  2. Internet porn use can lead to the 3 major addiction-related brain changes identified in substance addictions; and
  3. Internet porn use may exacerbate certain mental and emotional conditions (concentration problems, social anxiety, depression, etc.).  

The following is a short summary of empirical and clinical evidence supporting claims made in The Great Porn Experiment. Scroll down below it for slide-by-slide support.

1) Internet porn use can cause sexual dysfunctions:

2) Internet porn use can lead to the 3 major addiction-related brain changes identified in substance addictions:

The Great Porn Experiment listed ten internet addiction “brain studies,” which supported my thesis that internet addiction (and internet addiction subtypes such as gaming and porn) exists and involves the same fundamental mechanisms and brain changes as other addictions. This field of study is growing exponentially. As of 2017, there are some 250 internet addiction "brain studies." All of them report neurological findings and brain changes in internet addicts consistent with the addiction model (the list of Internet addiction "brain studies"). In addition, the design of several internet addiction studies supports the claim that internet use is causing (in some) symptoms such as depression, ADHD, anxiety, etc. The list of such studies: Studies demonstrating Internet use & porn use causing symptoms & brain changes.

The Great Porn Experiment described three major brain changes that occur with porn addiction: (1) Sensitization, (2) Desensitization, and (3) Dysfunctional prefrontal circuits (hypofrontality). Since March, 2012, much neurological research on porn users and porn addicts has been published. All three of these brain changes have been identified among the 37 neuroscience-based studies on frequent porn users and sex addicts:

  • Studies reporting sensitization or cue-reactivity in porn users/sex addicts: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.
  • Studies reporting desensitization or habituation in porn users/sex addicts: 1, 2, 3, 4, 5, 6.
  • Studies reporting poorer executive functioning (hypofrontality) or altered prefrontal activity in porn users/sex addicts: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13.

The 37 neuroscience-based studies (MRI, fMRI, EEG, neuropsychological, hormonal) provide strong support for the addiction model, as do the 13 recent literature reviews by some of the top neuroscientists in the world.

I also described escalation or habituation in my TEDx talk (which can be an indication of addiction). Three studies have now asked porn users specifically about escalation into new genres or tolerance, confirming both (1, 2, 3). Employing various indirect methods, an additional 16 studies have reported findings consistent with habituation to "regular porn" or escalation into more extreme and unusual genres.

Finally, it wasn’t until 2017 that two research teams asked internet-porn users directly about withdrawal symptoms. Both reported withdrawal symptoms in “problematic porn users” (1, 2).

What about neurological studies that debunk porn addiction? There are none. While the lead author of Prause et al., 2015 claimed her lone EEG study falsified pornography addiction, six peer-reviewed papers disagree: 1, 2, 3, 4, 5, 6. The neuroscientists on these six papers state that Prause et al. actually found desensitization/habituation (consistent with the development of addiction), as less brain activation to vanilla porn (pictures) was related to greater porn use. Unbelievably, the Prause et al. team boldly claimed to have falsified the porn addiction model with a single paragraph taken from this 2016 "letter to the editor." In reality the Prause letter falsified nothing, as this extensive critique reveals: Letter to the editor “Prause et al. (2015) the latest falsification of addiction predictions" (2016).

But ‘porn addiction’ isn’t in the APA's DSM-5, right? When the APA last updated the manual in 2013 (DSM-5), it didn’t formally consider “internet porn addiction,” opting instead to debate “hypersexual disorder.” The latter umbrella term for problematic sexual behavior was recommended for inclusion by the DSM-5’s own Sexuality Work Group after years of review. However, in an eleventh-hour “star chamber” session (according to a Work Group member), other DSM-5 officials unilaterally rejected hypersexuality, citing reasons that have been described as illogical.

Just prior to the DSM-5’s publication in 2013, Thomas Insel, then Director of the National Institute of Mental Health, warned that it was time for the mental health field to stop relying on the DSM. Its "weakness is its lack of validity," he explained, and "we cannot succeed if we use DSM categories as the "gold standard." He added, "That is why NIMH will be re-orienting its research away from DSM categories." In other words, the NIMH planned to stop funding research based on DSM labels (and their absence).

Major medical organizations are moving ahead of the APA. The American Society of Addiction Medicine (ASAM) hammered what should have been the final nail in the porn-addiction debate coffin in August, 2011, a few months before I prepared my TEDx talk. Top addiction experts at ASAM released their carefully crafted definition of addiction. The new definition makes some of the major points I made in my talk. Foremost, behavioral addictions affect the brain in the same fundamental ways as drugs do. In other words, addiction is essentially one disease (condition), not many. ASAM explicitly stated that sexual behavior addiction exists and must necessarily be caused by the same fundamental brain changes found in substance addictions.

The World Health Organization appears poised to set right the APA’s excessive caution. The next edition of its diagnostic manual, the ICD, is due out in 2018. The beta draft of the new ICD-11 includes a diagnosis for “Compulsive sexual behavior disorder,” as well as one for “Disorders due to addictive behaviors.”

3) Internet porn use may exacerbate certain mental and emotional conditions

The Great Porn Experiment described “The Other Porn Experiment” in which young men who eliminated porn use reported remission of emotional and cognitive problems. TGPE also described "arousal addiction" (internet addiction and its subtypes) exacerbating or causing symptoms such as brain fog, concentration problem, generalized anxiety, depression and social anxiety. As of 2017 there exist hundreds of correlative studies and a few dozen causation studies supporting this assertion.

Note: some of the links are to versions of the studies that appear on www.yourbrainonporn.com. Links there, lead to abstracts and full studies elsewhere.


POWERPOINT SLIDES 18-35 & ASSOCIATED TEXT


SLIDE 18

If the bingeing continues, it can lead to the brain changes seen in all addicts:

  1. First a numbed pleasure response kicks in - so everyday pleasures leave our porn addict dissatisfied (desensitization).
  2. At the same time, other physical changes make him hyper-reactive to porn (sensitization). Everything else in his life seems boring, but porn really fires up his reward circuit.
  3. Finally, his willpower erodes – as the CEO of his brain, the frontal cortex changes

 I can’t emphasize this enough: All addictions share these same brain changes and are triggered by the same molecular switch - DeltaFosB.

ORIGINAL SUPPORT:

Slide 18 claims that chronic bingeing on internet porn can leads to the same fundamental brain changes as seen in other types of addictions. The Great Porn Experiment described three major brain changes that occur with porn addiction: (1) Sensitization, (2) Desensitization, and (3) Dysfunctional prefrontal circuits (poorer executive functioning). The claim about DeltaFosB's role in cravings, compulsive consumption, and addiction was addressed on the previous slide.

The major brain changes involved with both drug and behavioral addictions (sensitization, desensitization, and dysfunctional prefrontal circuits/poorer executive function) had been delineated in several reviews of the literature, such as this paper by the head of NIDA, Nora Volkow: Addiction: Decreased Reward Sensitivity and Increased Expectation Sensitivity Conspire to Overwhelm the Brain's Control Circuit.

The claim that these same 3 brain changes occur in non-drug addictions was supported by hundreds of neurological studies showing that behavioral addictions (food addiction, pathological gambling, video gaming, and Internet addiction and porn addiction) and substance addictions share many of the same fundamental mechanisms leading to a collection of shared alterations in brain anatomy and chemistry. This was not surprising as drugs can only enhance or inhibit existing physiological functions.

For example, all addictive drugs and potentially addictive behaviors share one important mechanism of action: elevation of dopamine in the nucleus accumbens (also called the reward center). Chronic overconsumption, and associated dopamine spikes, cause ΔFosB to accumulate gradually in key areas of the brain. (ΔFosB is a transcription factor, i.e., a protein that binds to your genes and turns them on or off.)  DeltaFosB alters our genes' responses, bringing on measurable, physical brain changes. These begin with sensitization, i.e., hyper-reactivity of the brain's reward circuitry—but only in response to the specific cues it associates with the developing addiction. According to researcher Eric Nestler,

[ΔFosB is] almost like a molecular switch. ... Once it's flipped on, it stays on for a while and doesn't go away easily. This phenomenon is observed in response to chronic administration of virtually any drug of abuse. It is also observed after high levels of consumption of natural rewards (exercise, sucrose, high fat diet, sex).

I'll include a few reviews of the literature supporting the existence of behavioral addictions (for simplicity, some published after my talk are also listed):

  1. The Neurobiology and Genetics of Impulse Control Disorders: Relationships to Drug Addictions (2008)
  2. Shared Brain Vulnerabilities Open The Way For Nonsubstance Addictions: Carving Addiction at a New Joint? (2010)
  3. Introduction to Behavioral Addictions (2010)
  4. Probing Compulsive and Impulsive Behaviors, from Animal Models to Endophenotypes: A Narrative Review (2010)
  5. Natural Rewards, Neuroplasticity, and Non-Drug Addictions (2011)
  6. A Targeted Review of the Neurobiology and Genetics of Behavioral Addictions: An Emerging Area of Research (2013)
  7. A neurocognitive approach to understanding the neurobiology of addiction (2013)
  8. The functional anatomy of impulse control disorders (2013)
  9. Perspective: Behavioural Addictions Matter, Mark Potenza (2015)
  10. Behavioral addictions in addiction medicine: from mechanisms to practical considerations (2016)
  11. Dimensionality of Cognitions in Behavioral Addiction (2016)
  12. Roles of "Wanting" and "Liking" in Motivating Behavior: Gambling, Food, and Drug Addictions (2016)
  13. Transitionality in addiction: A “temporal continuum” hypotheses involving the aberrant motivation, the hedonic dysregulation, and the aberrant learning (2016)
  14. Behavioural addiction and substance addiction should be defined by their similarities not their dissimilarities (2017)
  15. Substance and behavioral addictions may share a similar underlying process of dysregulation (2017)

The following pages contain hundreds of neurological studies describing mechanisms and brain changes consistent with the addiction model:

As described earlier, Norman Doidge's 2007 bestseller The Brain That Changes Itself claimed that behavioral addictions (including internet pornography) exist. Excerpt in support of this slide:

The addictiveness of Internet pornography is not a metaphor. Not all addictions are to drugs or alcohol. People can be seriously addicted to gambling, even to running. All addicts show a loss of control of the activity, compulsively seek it out despite negative consequences, develop tolerance so that they need higher and higher levels of stimulation for satisfaction, and experience withdrawal if they can't consummate the addictive act.

All addiction involves long-term, sometimes lifelong, neuroplastic change in the brain. For addicts, moderation is impossible, and they must avoid the substance or activity completely if they are to avoid addictive behaviors.

In 2011, only three neurological studies had been published (two on "hypersexuals", one on internet porn users). All three reported neurological markers consistent with the addiction model:

1) Preliminary Investigation of The Impulsive And Neuroanatomical Characteristics of Compulsive Sexual Behavior (2009) - (poorer executive functioning) Primarily sex addicts. Study reports more impulsive behavior in a Go-NoGo task in sex addicts (hypersexuals) compared to control participants. Brain scans revealed that sex addicts had greater disorganized prefrontal cortex white matter. This finding is consistent with hypofrontality, a hallmark of addiction.

2) Self-reported differences on measures of executive function and hypersexual behavior in a patient and community sample of men (2010) - (poorer executive functioning). Excerpt:

Patients seeking help for hypersexual behavior often exhibit features of impulsivity, cognitive rigidity, poor judgment, deficits in emotion regulation, and excessive preoccupation with sex. Some of these characteristics are also common among patients presenting with neurological pathology associated with executive dysfunction. These observations led to the current investigation of differences between a group of hypersexual patients (n = 87) and a non-hypersexual community sample (n = 92) of men using the Behavior Rating Inventory of Executive Function-Adult Version  Hypersexual behavior was positively correlated with global indices of executive dysfunction and several subscales of the BRIEF-A. These findings provide preliminary evidence supporting the hypothesis that executive dysfunction may be implicated in hypersexual behavior.

3) Watching Pornographic Pictures on the Internet: Role of Sexual Arousal Ratings and Psychological-Psychiatric Symptoms for Using Internet Sex Sites Excessively (2011) - (poorer executive functioning). Excerpt:

Results indicate that self-reported problems in daily life linked to online sexual activities were predicted by subjective sexual arousal ratings of the pornographic material, global severity of psychological symptoms, and the number of sex applications used when being on Internet sex sites in daily life, while the time spent on Internet sex sites (minutes per day) did not significantly contribute to explanation of variance in IATsex score. We see some parallels between cognitive and brain mechanisms potentially contributing to the maintenance of excessive cybersex and those described for individuals with substance dependence

Finally, the claims of Slide 18 were based on a principle put forth by a large organization devoted to addiction medicine and research, The American Society of Addiction Medicine (ASAM), in their 2011 “New Definition of Addiction": Exhibiting the signs, symptoms and behaviors consistent with addiction indicates a constellation of underlying brain changes has occurred (such as: Sensitization, Desensitization, Dysfunctional prefrontal circuits (hypofrontality), Dysfunctional stress circuits). I felt ASAM's new definition ended the debate over whether sex and porn addictions are "real addictions." From the ASAM press release:

The new definition resulted from an intensive, four‐year process with more than 80 experts actively working on it, including top addiction authorities, addiction medicine clinicians and leading neuroscience researchers from across the country. ... Two decades of advancements in neurosciences convinced ASAM that addiction needed to be redefined by what's going on in the brain.

Research showed that both behavioral and chemical addictions entail the same major alterations in brain anatomy and physiology. An ASAM spokesman explained:

The new definition leaves no doubt that all addictions—whether to alcohol, heroin or sex, say—are fundamentally the same. Dr. Raju Haleja, former president of the Canadian Society for Addiction Medicine and the chair of the ASAM committee that crafted the new definition, told The Fix, "We are looking at addiction as one disease, as opposed to those who see them as separate diseases. Addiction is addiction. It doesn't matter what cranks your brain in that direction, once it has changed direction, you're vulnerable to all addiction." ...Sex or gambling or food addiction [are] every bit as medically valid as addiction to alcohol or heroin or crystal meth.

An excerpt from ASAM's FAQs

QUESTION: What's different about this new definition?

ANSWER: The focus in the past has been generally on substances associated with addiction, such as alcohol, heroin, marijuana, or cocaine. This new definition makes clear that addiction is not about drugs, it's about brains. It is not the substances a person uses that make them an addict; it is not even the quantity or frequency of use. Addiction is about what happens in a person's brain when they are exposed to rewarding substances or rewarding behaviors, and it is more about reward circuitry in the brain and related brain structures than it is about the external chemicals or behavior that "turn on" that reward circuitry.

A brief summary of ASAM's major points:

  1. Addiction reflects the same general brain changes whether it arises in response to chemicals or behaviors.
  2. Addiction is a primary illness. It's not necessarily caused by mental health issues such as mood or personality disorders. This puts to rest the popular notion that addictive behaviors are always a form of "self-medication" to ease other disorders.
  3. Both behavioral and substance addictions cause the same major changes in the same neural circuitry: Hypofrontality, sensitization, desensitization, altered stress circuits, etc.
  4. The new definition eradicates the old "addiction vs. compulsion" distinction, which was often used to deny the existence of behavioral addictions, including “sexual behavior addictions.”

Excerpts from ASAM's FAQs related to sex and pornography addiction (ASAM mentioned “sexual behavior addiction” 10 times in its 2011 definition and FAQs - more than all other addictions combined.):

QUESTION: This new definition of addiction refers to addiction involving gambling, food, and sexual behaviors. Does ASAM really believe that food and sex are addicting?

ANSWER: Addiction to gambling has been well described in the scientific literature for several decades. In fact, the latest edition of the DSM (DSM-5) will list gambling disorder in the same section with substance use disorders. The new ASAM definition makes a departure from equating addiction with just substance dependence, by describing how addiction is also related to behaviors that are rewarding. This the first time that ASAM has taken an official position that addiction is not solely "substance dependence." This definition says that addiction is about functioning and brain circuitry and how the structure and function of the brains of persons with addiction differ from the structure and function of the brains of persons who do not have addiction. It talks about reward circuitry in the brain and related circuitry, but the emphasis is not on the external rewards that act on the reward system. Food and sexual behaviors and gambling behaviors can be associated with the "pathological pursuit of rewards" described in this new definition of addiction.

QUESTION: Who has food addiction or sex addiction?

ANSWER: We all have the brain reward circuitry that makes food and sex rewarding. In fact, this is a survival mechanism. In a healthy brain, these rewards have feedback mechanisms for satiety or 'enough.' In someone with addiction, the circuitry becomes dysfunctional such that the message to the individual becomes 'more', which leads to the pathological pursuit of rewards and/or relief through the use of substances and behaviors.

UPDATED SUPPORT:

The claims put forth on Slide 18 are now fully supported by the research. "Updated support" for Slide 18 is divided into four sections:

  1. Neurological studies on porn users and "sex addicts"
  2. Reviews of the literature or narrative reviews
  3. Behavioral addictions and the DSM and ICD
  4. Unsupported claims

Neurological studies on porn users and "sex addicts":

This landmark review by the Director of the National Institute on Alcohol Abuse and Alcoholism (NIAAA) George F. Koob, and the director of the National Institute on Drug Abuse (NIDA) Nora D. Volkow, was published in The New England Journal of Medicine: Neurobiologic Advances from the Brain Disease Model of Addiction (2016)." The paper describes the major brain changes involved with both drug and behavioral addictions, while stating in its opening paragraph that sex addiction exists:

"We conclude that neuroscience continues to support the brain disease model of addiction. Neuroscience research in this area not only offers new opportunities for the prevention and treatment of substance addictions and related behavioral addictions (e.g., to food, sex, and gambling)...."

The Volkow & Koob paper outlined the three brain changes presented in Slide 18 (sensitization, desensitization, dysfunctional prefrontal circuits), along with a fourth - dysfunctional stress system. Since March, 2012, much neurological research on porn users and porn addicts has been published. All four of these brain changes have been identified among the 37 neuroscience-based studies on frequent porn users and sex addicts:

  • Studies reporting sensitization or cue-reactivity in porn users/sex addicts: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.
  • Studies reporting desensitization or habituation in porn users/sex addicts: 1, 2, 3, 4, 5, 6.
  • Studies reporting poorer executive functioning (hypofrontality) or altered prefrontal activity in porn users/sex addicts: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13.
  • Studies indicating a dysfunctional stress system in porn users/sex addicts: 1, 2, 3.

Each neurological study contains a description or excerpt and lists which of the 4 addiction-related brain change(s) just listed that its findings endorse (I've included the 3 studies published before 2012):

1) Preliminary Investigation of The Impulsive And Neuroanatomical Characteristics of Compulsive Sexual Behavior (2009) - [dysfunctional prefrontal circuits/poorer executive function] – fMRI study involving primarily sex addicts. Study reports more impulsive behavior in a Go-NoGo task in sex addicts (hypersexuals) compared to control participants. Brain scans revealed that sex addicts had disorganized prefrontal cortex white matter compared to controls. Excerpts:

In addition to the above self-report measures, CSB patients also showed significantly more impulsivity on a behavioral task, the Go-No Go procedure.

Results also indicate that CSB patients showed significantly higher superior frontal region mean diffusivity (MD) than controls. A correlational analysis indicated significant associations between impulsivity measures and inferior frontal region fractional anisotrophy (FA) and MD, but no associations with superior frontal region measures. Similar analyses indicated a significant negative association between superior frontal lobe MD and the compulsive sexual behavior inventory.

2) Self-reported differences on measures of executive function and hypersexual behavior in a patient and community sample of men (2010) - [poorer executive function] – An excerpt:

Patients seeking help for hypersexual behavior often exhibit features of impulsivity, cognitive rigidity, poor judgment, deficits in emotion regulation, and excessive preoccupation with sex. Some of these characteristics are also common among patients presenting with neurological pathology associated with executive dysfunction. These observations led to the current investigation of differences between a group of hypersexual patients (n = 87) and a non-hypersexual community sample (n = 92) of men using the Behavior Rating Inventory of Executive Function-Adult Version  Hypersexual behavior was positively correlated with global indices of executive dysfunction and several subscales of the BRIEF-A. These findings provide preliminary evidence supporting the hypothesis that executive dysfunction may be implicated in hypersexual behavior.

3) Watching Pornographic Pictures on the Internet: Role of Sexual Arousal Ratings and Psychological-Psychiatric Symptoms for Using Internet Sex Sites Excessively (2011) - [greater cravings/sensitization and poorer executive function] – An excerpt:

Results indicate that self-reported problems in daily life linked to online sexual activities were predicted by subjective sexual arousal ratings of the pornographic material, global severity of psychological symptoms, and the number of sex applications used when being on Internet sex sites in daily life, while the time spent on Internet sex sites (minutes per day) did not significantly contribute to explanation of variance in IATsex score. We see some parallels between cognitive and brain mechanisms potentially contributing to the maintenance of excessive cybersex and those described for individuals with substance dependence.

4) Pornographic Picture Processing Interferes with Working Memory Performance (2013) [greater cravings/sensitization and poorer executive function] – An excerpt:

Some individuals report problems during and after Internet sex engagement, such as missing sleep and forgetting appointments, which are associated with negative life consequences. One mechanism potentially leading to these kinds of problems is that sexual arousal during Internet sex might interfere with working memory (WM) capacity, resulting in a neglect of relevant environmental information and therefore disadvantageous decision making. Results revealed worse WM performance in the pornographic picture condition of the 4-back task compared with the three remaining picture conditions. Findings are discussed with respect to Internet addiction because WM interference by addiction-related cues is well known from substance dependencies.

5) Sexual Picture Processing Interferes with Decision-Making Under Ambiguity (2013) [greater cravings/sensitization and poorer executive function] – An excerpt:

Decision-making performance was worse when sexual pictures were associated with disadvantageous card decks compared to performance when the sexual pictures were linked to the advantageous decks. Subjective sexual arousal moderated the relationship between task condition and decision-making performance. This study emphasized that sexual arousal interfered with decision-making, which may explain why some individuals experience negative consequences in the context of cybersex use.

6) Cybersex addiction: Experienced sexual arousal when watching pornography and not real-life sexual contacts makes the difference (2013) - [greater cravings/sensitization and poorer executive function] – An excerpt:

The results show that indicators of sexual arousal and craving to Internet pornographic cues predicted tendencies towards cybersex addiction in the first study. Moreover, it was shown that problematic cybersex users report greater sexual arousal and craving reactions resulting from pornographic cue presentation. In both studies, the number and the quality with real-life sexual contacts were not associated to cybersex addiction. The results support the gratification hypothesis, which assumes reinforcement, learning mechanisms, and craving to be relevant processes in the development and maintenance of cybersex addiction. Poor or unsatisfying sexual real life contacts cannot sufficiently explain cybersex addiction.

7) Sexual Desire, not Hypersexuality, is Related to Neurophysiological Responses Elicited by Sexual Images (2013) - [greater cue-reactivity correlated with less sexual desire: sensitization and habituation] -This EEG study was touted in the media as evidence against the existence of porn/sex addiction. Not so. Steele et al. actually lends support to the existence of both porn addiction and porn use down-regulating sexual desire. How so? The study reported higher EEG readings (relative to neutral pictures) when subjects were briefly exposed to pornographic photos. Studies consistently show that an elevated P300 occurs when addicts are exposed to cues (such as images) related to their addiction.

However, due to methodological flaws the findings are in doubt: 1) the study had no control group for comparison; 2) subjects were heterogeneous (males, females, non-heterosexuals); 3) subjects were not screened for mental disorders or addictions; 4) the questionnaires were not validated for porn addiction.

In line with the Cambridge University brain scan studies, this EEG study also reported greater cue-reactivity to porn correlating with less desire for partnered sex. To put it another way - individuals with greater brain activation to porn would rather masturbate to porn than have sex with a real person. Shockingly, study spokesperson Nicole Prause claimed that porn users merely had "high libido," yet the results of the study say the exact opposite (subjects' desire for partnered sex was dropping in relation to their porn use). Five peer-reviewed papers explain the truth: 1, 2, 3, 4, 5. Also see an extensive YBOP critique.

8) Brain Structure and Functional Connectivity Associated With Pornography Consumption: The Brain on Porn (2014) – [desensitization, habituation, and dysfunctional prefrontal circuits]. This Max Planck Institute fMRI study reported 3 neurological findings correlating with higher levels of porn use: (1) less reward system grey matter (dorsal striatum), (2) less reward circuit activation while briefly viewing sexual photos, (3) poorer functional connectivity between the dorsal striatum and dorsolateral prefrontal cortex. The researchers interpreted the 3 findings as an indication of the effects of longer-term porn exposure. Said the study,

This is in line with the hypothesis that intense exposure to pornographic stimuli results in a down-regulation of the natural neural response to sexual stimuli.

In describing the poorer functional connectivity between the PFC and the striatum the study said,

Dysfunction of this circuitry has been related to inappropriate behavioral choices, such as drug seeking, regardless of the potential negative outcome

Lead author Simone Kühn commenting in an article about the findings said:

We assume that subjects with a high porn consumption need increasing stimulation to receive the same amount of reward. That could mean that regular consumption of pornography more or less wears out your reward system. That would fit perfectly the hypothesis that their reward systems need growing stimulation.

9) Neural Correlates of Sexual Cue Reactivity in Individuals with and without Compulsive Sexual Behaviours (2014) – [sensitization/cue-reactivity and desensitization] The first in a series of Cambridge University studies found the same brain activity pattern in porn addicts (CSB subjects) as seen in drug addicts and alcoholics – greater cue-reactivity or sensitization. Lead researcher Valerie Voon said:

There are clear differences in brain activity between patients who have compulsive sexual behaviour and healthy volunteers. These differences mirror those of drug addicts.

Voon et al., 2014 also found that porn addicts fit the accepted addiction model of wanting "it" more, but not liking "it" any more. Excerpt:

Compared to healthy volunteers, CSB subjects had greater subjective sexual desire or wanting to explicit cues and had greater liking scores to erotic cues, thus demonstrating a dissociation between wanting and liking

The researchers also reported that 60% of subjects (average age: 25) had difficulty achieving erections/arousal with real partners, yet could achieve erections with porn. This indicates sensitization or habituation. Excerpts:

CSB subjects reported that as a result of excessive use of sexually explicit materials..... experienced diminished libido or erectile function specifically in physical relationships with women (although not in relationship to the sexually explicit material)…

CSB subjects compared to healthy volunteers had significantly more difficulty with sexual arousal and experienced more erectile difficulties in intimate sexual relationships but not to sexually explicit material.

10) Enhanced Attentional Bias towards Sexually Explicit Cues in Individuals with and without Compulsive Sexual Behaviours (2014) - [sensitization/cue-reactivity] - The second Cambridge University study. An excerpt:

Our findings of enhanced attentional bias... suggest possible overlaps with enhanced attentional bias observed in studies of drug cues in disorders of addictions. These findings converge with recent findings of neural reactivity to sexually explicit cues in [porn addicts] in a network similar to that implicated in drug-cue-reactivity studies and provide support for incentive motivation theories of addiction underlying the aberrant response to sexual cues in [porn addicts]. This finding dovetails with our recent observation that sexually explicit videos were associated with greater activity in a neural network similar to that observed in drug-cue-reactivity studies. Greater desire or wanting rather than liking was further associated with activity in this neural network. These studies together provide support for an incentive motivation theory of addiction underlying the aberrant response towards sexual cues in CSB.

11) Cybersex addiction in heterosexual female users of internet pornography can be explained by gratification hypothesis (2014) - [greater cravings/sensitization] - An excerpt:

We examined 51 female IPU and 51 female non-Internet pornography users (NIPU). Using questionnaires, we assessed the severity of cybersex addiction in general, as well as propensity for sexual excitation, general problematic sexual behavior, and severity of psychological symptoms. Additionally, an experimental paradigm, including a subjective arousal rating of 100 pornographic pictures, as well as indicators of craving, was conducted. Results indicated that IPU rated pornographic pictures as more arousing and reported greater craving due to pornographic picture presentation compared with NIPU. Moreover, craving, sexual arousal rating of pictures, sensitivity to sexual excitation, problematic sexual behavior, and severity of psychological symptoms predicted tendencies toward cybersex addiction in IPU. Being in a relationship, number of sexual contacts, satisfaction with sexual contacts, and use of interactive cybersex were not associated with cybersex addiction. These results are in line with those reported for heterosexual males in previous studies. Findings regarding the reinforcing nature of sexual arousal, the mechanisms of learning, and the role of cue reactivity and craving in the development of cybersex addiction in IPU need to be discussed.

12) Empirical Evidence and Theoretical Considerations on Factors Contributing to Cybersex Addiction From a Cognitive Behavioral View (2014) - [greater cravings/sensitization] - An excerpt:

The nature of a phenomenon often called cybersex addiction (CA) and its mechanisms of development are discussed. Previous work suggests that some individuals might be vulnerable to CA, while positive reinforcement and cue-reactivity are considered to be core mechanisms of CA development. In this study, 155 heterosexual males rated 100 pornographic pictures and indicated their increase of sexual arousal. Moreover, tendencies towards CA, sensitivity to sexual excitation, and dysfunctional use of sex in general were assessed. The results of the study show that there are factors of vulnerability to CA and provide evidence for the role of sexual gratification and dysfunctional coping in the development of CA.

13) Novelty, Conditioning and Attentional Bias to Sexual Rewards (2015) - [greater cravings/sensitization and habituation/desensitization] - Another Cambridge University fMRI study. Compared to controls porn addicts preferred sexual novelty and conditioned cues associated porn. However, the brains of porn addicts habituated faster to sexual images. Since novelty preference wasn't pre-existing, it is believed that porn addiction drives novelty-seeking in an attempt to overcome habituation and desensitization.

Compulsive sexual behavior (CSB) was associated with enhanced novelty preference for sexual, as compared to control images, and a generalized preference for cues conditioned to sexual and monetary versus neutral outcomes compared to healthy volunteers. CSB individuals also had greater dorsal cingulate habituation to repeated sexual versus monetary images with the degree of habituation correlating with enhanced preference for sexual novelty. Approach behaviors to sexually conditioned cues dissociable from novelty preference were associated with an early attentional bias to sexual images. This study shows that CSB individuals have a dysfunctional enhanced preference for sexual novelty possibly mediated by greater cingulate habituation along with a generalized enhancement of conditioning to rewards. An excerpt:

An excerpt from the related press release:

They found that when the sex addicts viewed the same sexual image repeatedly, compared to the healthy volunteers they experienced a greater decrease of activity in the region of the brain known as the dorsal anterior cingulate cortex, known to be involved in anticipating rewards and responding to new events. This is consistent with 'habituation', where the addict finds the same stimulus less and less rewarding – for example, a coffee drinker may get a caffeine 'buzz' from their first cup, but over time the more they drink coffee, the smaller the buzz becomes.

This same habituation effect occurs in healthy males who are repeatedly shown the same porn video. But when they then view a new video, the level of interest and arousal goes back to the original level. This implies that, to prevent habituation, the sex addict would need to seek out a constant supply of new images. In other words, habituation could drive the search for novel images.

"Our findings are particularly relevant in the context of online pornography," adds Dr Voon. "It's not clear what triggers sex addiction in the first place and it is likely that some people are more pre-disposed to the addiction than others, but the seemingly endless supply of novel sexual images available online helps feed their addiction, making it more and more difficult to escape."

14) Neural Substrates of Sexual Desire in Individuals with Problematic Hypersexual Behavior (2015) - [greater cue reactivity/sensitization and dysfunctional prefrontal circuits] - This Korean fMRI study replicates other brain studies on porn users. Like the Cambridge University studies it found cue-induced brain activation patterns in sex addicts, which mirrored the patterns of drug addicts. In line with several German studies it found alterations in the prefrontal cortex which match the changes observed in drug addicts. What's new is that the findings matched the prefrontal cortex activation patterns observed in drug addicts: Greater cue-reactivity to sexual images yet inhibited responses to other normally salient stimuli. An excerpt:

Our study aimed to investigate the neural correlates of sexual desire with event-related functional magnetic resonance imaging (fMRI). Twenty-three individuals with PHB and 22 age-matched healthy controls were scanned while they passively viewed sexual and nonsexual stimuli. The subjects' levels of sexual desire were assessed in response to each sexual stimulus. Relative to controls, individuals with PHB experienced more frequent and enhanced sexual desire during exposure to sexual stimuli. Greater activation was observed in the caudate nucleus, inferior parietal lobe, dorsal anterior cingulate gyrus, thalamus, and dorsolateral prefrontal cortex in the PHB group than in the control group. In addition, the hemodynamic patterns in the activated areas differed between the groups. Consistent with the findings of brain imaging studies of substance and behavior addiction, individuals with the behavioral characteristics of PHB and enhanced desire exhibited altered activation in the prefrontal cortex and subcortical regions

15) Modulation of Late Positive Potentials by Sexual Images in Problem Users and Controls Inconsistent with "Porn Addiction" (2015) – [habituation] - A second EEG study from Prause's team. This study compared the 2013 subjects from Steele et al., 2013 to an actual control group (yet it suffered from the same methodological flaws named above). The results: Compared to controls "individuals experiencing problems regulating their porn viewing" had lower brain responses to one-second exposure to photos of vanilla porn. The lead author claims these results "debunk porn addiction." What legitimate scientist would claim that their lone anomalous study has debunked a well established field of study?

In reality, the findings of Prause et al. 2015 align perfectly with Kühn & Gallinat (2014), which found that more porn use correlated with less brain activation in response to pictures of vanilla porn. Prause et al findings also align with Banca et al. 2015 which is #13 in this list. Moreover, another EEG study found that greater porn use in women correlated with less brain activation to porn. Lower EEG readings mean that subjects are paying less attention to the pictures. Put simply, frequent porn users were desensitized to static images of vanilla porn. They were bored (habituated or desensitized). See this extensive YBOP critique. Six peer-reviewed papers agree that this study actually found desensitization/habituation in frequent porn users (consistent with addiction): 1, 2, 3, 4, 5, 6.

16) HPA Axis Dysregulation in Men With Hypersexual Disorder (2015) - [dysfunctional stress response] - A study with 67 male sex addicts and 39 age-matched controls. The Hypothalamus-Pituitary-Adrenal (HPA) axis is the central player in our stress response. Addictions alter the brain's stress circuits leading to a dysfunctional HPA axis. This study on sex addicts (hypersexuals) found altered stress responses that mirror the findings with substance addictions. Excerpts from press release:

The study involved 67 men with hypersexual disorder and 39 healthy matched controls. The participants were carefully diagnosed for hypersexual disorder and any co-morbidity with depression or childhood trauma. The researchers gave them a low dose of dexamethasone on the evening before the test to inhibit their physiological stress response, and then in the morning measured their levels of stress hormones cortisol and ACTH. They found that patients with hypersexual disorder had higher levels of such hormones than the healthy controls, a difference that remained even after controlling for co-morbid depression and childhood trauma.

"Aberrant stress regulation has previously been observed in depressed and suicidal patients as well as in substance abusers," says Professor Jokinen. "In recent years, the focus has been on whether childhood trauma can lead to a dysregulation of the body's stress systems via so-called epigenetic mechanisms, in other words how their psychosocial environments can influence the genes that control these systems." According to the researchers, the results suggest that the same neurobiological system involved in another type of abuse can apply to people with hypersexual disorder.

17) Prefrontal control and internet addiction: a theoretical model and review of neuropsychological and neuroimaging findings (2015) - [dysfunctional prefrontal circuits/poorer executive function and sensitization] – Excerpt:

Consistent with this, results from functional neuroimaging and other neuropsychological studies demonstrate that cue-reactivity, craving, and decision making are important concepts for understanding Internet addiction. The findings on reductions in executive control are consistent with other behavioral addictions, such as pathological gambling. They also emphasize the classification of the phenomenon as an addiction, because there are also several similarities with findings in substance dependency.  Moreover, the results of the current study are comparable to findings from substance dependency research and emphasize analogies between cybersex addiction and substance dependencies or other behavioral addictions.

18) Implicit associations in cybersex addiction: Adaption of an Implicit Association Test with pornographic pictures. (2015) - [greater cravings/sensitization] – Excerpt:

Recent studies show similarities between cybersex addiction and substance dependencies and argue to classify cybersex addiction as a behavioral addiction. In substance dependency, implicit associations are known to play a crucial role, and such implicit associations have not been studied in cybersex addiction, so far. In this experimental study, 128 heterosexual male participants completed an Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998) modified with pornographic pictures. Further, problematic sexual behavior, sensitivity towards sexual excitation, tendencies towards cybersex addiction, and subjective craving due to watching pornographic pictures were assessed. Results show positive relationships between implicit associations of pornographic pictures with positive emotions and tendencies towards cybersex addiction, problematic sexual behavior, sensitivity towards sexual excitation as well as subjective craving. Moreover, a moderated regression analysis revealed that individuals who reported high subjective craving and showed positive implicit associations of pornographic pictures with positive emotions, particularly tended towards cybersex addiction. The findings suggest a potential role of positive implicit associations with pornographic pictures in the development and maintenance of cybersex addiction. Moreover, the results of the current study are comparable to findings from substance dependency research and emphasize analogies between cybersex addiction and substance dependencies or other behavioral addictions.

19) Symptoms of cybersex addiction can be linked to both approaching and avoiding pornographic stimuli: results from an analog sample of regular cybersex users (2015) - [greater cravings/sensitization] – Excerpt:

Some approaches point toward similarities to substance dependencies for which approach/avoidance tendencies are crucial mechanisms. Several researchers have argued that within an addiction-related decision situation, individuals might either show tendencies to approach or avoid addiction-related stimuli. In the current study 123 heterosexual males completed an Approach-Avoidance-Task (AAT; Rinck and Becker, 2007) modified with pornographic pictures. During the AAT participants either had to push pornographic stimuli away or pull them toward themselves with a joystick. Sensitivity toward sexual excitation, problematic sexual behavior, and tendencies toward cybersex addiction were assessed with questionnaires.

Results showed that individuals with tendencies toward cybersex addiction tended to either approach or avoid pornographic stimuli. Additionally, moderated regression analyses revealed that individuals with high sexual excitation and problematic sexual behavior who showed high approach/avoidance tendencies, reported higher symptoms of cybersex addiction. Analogous to substance dependencies, results suggest that both approach and avoidance tendencies might play a role in cybersex addiction. Moreover, an interaction with sensitivity toward sexual excitation and problematic sexual behavior could have an accumulating effect on the severity of subjective complaints in everyday life due to cybersex use. The findings provide further empirical evidence for similarities between cybersex addiction and substance dependencies. Such similarities could be retraced to a comparable neural processing of cybersex- and drug-related cues.

20) Getting stuck with pornography? Overuse or neglect of cybersex cues in a multitasking situation is related to symptoms of cybersex addiction (2015) - [greater cravings/sensitization and poorer executive control] – Excerpt:

Some individuals consume cybersex contents, such as pornographic material, in an addictive manner, which leads to severe negative consequences in private life or work. One mechanism leading to negative consequences may be reduced executive control over cognition and behavior that may be necessary to realize goal-oriented switching between cybersex use and other tasks and obligations of life. To address this aspect, we investigated 104 male participants with an executive multitasking paradigm with two sets: One set consisted of pictures of persons, the other set consisted of pornographic pictures. In both sets the pictures had to be classified according to certain criteria. The explicit goal was to work on all classification tasks to equal amounts, by switching between the sets and classification tasks in a balanced manner.

We found that less balanced performance in this multitasking paradigm was associated with a higher tendency towards cybersex addiction. Persons with this tendency often either overused or neglected working on the pornographic pictures. The results indicate that reduced executive control over multitasking performance, when being confronted with pornographic material, may contribute to dysfunctional behaviors and negative consequences resulting from cybersex addiction. However, individuals with tendencies towards cybersex addiction seem to have either an inclination to avoid or to approach the pornographic material, as discussed in motivational models of addiction.

21) Trading Later Rewards for Current Pleasure: Pornography Consumption and Delay Discounting (2015) - [poorer executive control: causation experiment] – Excerpts:

Study 1: Participants completed a pornography use questionnaire and a delay discounting task at Time 1 and then again four weeks later. Participants reporting higher initial pornography use demonstrated a higher delay discounting rate at Time 2, controlling for initial delay discounting. Study 2:  Participants who abstained from pornography use demonstrated lower delay discounting than participants who abstained from their favorite food.

Internet pornography is a sexual reward that contributes to delay discounting differently than other natural rewards do, even when use is not compulsive or addictive. This research makes an important contribution, demonstrating that the effect goes beyond temporary arousal.

Pornography consumption may provide immediate sexual gratification but can have implications that transcend and affect other domains of a person’s life, especially relationships.

The finding suggests that Internet pornography is a sexual reward that contributes to delay discounting differently than other natural rewards. It is therefore important to treat pornography as a unique stimulus in reward, impulsivity, and addiction studies and to apply this accordingly in individual as well as relational treatment.

22) Sexual Excitability and Dysfunctional Coping Determine Cybersex Addiction in Homosexual Males (2015) - [greater cravings/sensitization] – Excerpt:

Recent findings have demonstrated an association between CyberSex Addiction (CA) severity and indicators of sexual excitability, and that coping by sexual behaviors mediated the relationship between sexual excitability and CA symptoms. The aim of this study was to test this mediation in a sample of homosexual males. Questionnaires assessed symptoms of CA, sensitivity to sexual excitation, pornography use motivation, problematic sexual behavior, psychological symptoms, and sexual behaviors in real life and online. Moreover, participants viewed pornographic videos and indicated their sexual arousal before and after the video presentation. Results showed strong correlations between CA symptoms and indicators of sexual arousal and sexual excitability, coping by sexual behaviors, and psychological symptoms. CA was not associated with offline sexual behaviors and weekly cybersex use time. Coping by sexual behaviors partially mediated the relationship between sexual excitability and CA. The results are comparable with those reported for heterosexual males and females in previous studies and are discussed against the background of theoretical assumptions of CA, which highlight the role of positive and negative reinforcement due to cybersex use.

23) The Role of Neuroinflammation in the Pathophysiology of Hypersexual Disorder (2016) - [dysfunctional stress response and inflammation] - This study reported higher levels of circulating Tumor Necrosis Factor (TNF) in sex addicts when compared to healthy controls. Elevated levels of TNF (a marker of inflammation) have also been found in substance abusers and drug-addicted animals (alcohol, heroin, meth). There were strong correlations between TNF levels and rating scales measuring hypersexuality.

24) Methylation of HPA Axis Related Genes in Men With Hypersexual Disorder (2017) - [dysfunctional stress response] - This is a follow-up of #8 above which found that sex addicts have dysfunctional stress systems - a key neuro-endocrine change caused by addiction. The current study found epigenetic changes on genes central to the human stress response and closely associated with addiction. With epigenetic changes, the DNA sequence isn't altered (as happens with a mutation). Instead, the gene is tagged and its expression is turned up or down (short video explaining epigenetics). The epigenetic changes reported in this study resulted in altered CRF gene activity. CRF is a neurotransmitter and hormone that drives addictive behaviors such as cravings, and is a major player in many of the withdrawal symptoms experienced in connection with substance and behavioral addictions, including porn addiction.

25) Compulsive Sexual Behavior: Prefrontal And Limbic Volume and Interactions (2016) - [dysfunctional prefrontal circuits and sensitization] - This is an fMRI study. Compared to healthy controls CSB subjects (porn addicts) had increased left amygdala volume and reduced functional connectivity between the amygdala and dorsolateral prefrontal cortex DLPFC. Reduced functional connectivity between the amygdala and the prefrontal cortex aligns with substance addictions. It is thought that poorer connectivity diminishes the prefrontal cortex's control over a user's impulse to engage in the addictive behavior. This study suggests that drug toxicity may lead to less grey matter and thus reduced amygdala volume in drug addicts. The amygdala is consistently active during porn viewing, especially during initial exposure to a sexual cue. Perhaps the constant sexual novelty and searching and seeking leads to a unique effect on the amygdala in compulsive porn users. Alternatively, years of porn addiction and severe negative consequences are very stressful - and chronic social stress is related to increased amygdala volume. Study #16 above found that "sex addicts" have an overactive stress system. Could the chronic stress related to porn/sex addiction, along with factors that make sex unique, lead to greater amygdala volume? An excerpt:

Our current findings highlight elevated volumes in a region implicated in motivational salience and lower resting state connectivity of prefrontal top-down regulatory control networks. Disruption of such networks may explain the aberrant behavioral patterns toward environmentally salient reward or enhanced reactivity to salient incentive cues. Although our volumetric findings contrast with those in SUD, these findings may reflect differences as a function of the neurotoxic effects of chronic drug exposure. Emerging evidence suggests potential overlaps with an addiction process particularly supporting incentive motivation theories. We have shown that activity in this salience network is then enhanced following exposure to highly salient or preferred sexually explicit cues [Brand et al., 2016; Seok and Sohn, 2015; Voon et al., 2014] along with enhanced attentional bias [Mechelmans et al., 2014] and desire specific to the sexual cue but not generalized sexual desire [Brand et al., 2016; Voon et al., 2014]. Enhanced attention to sexually explicit cues is further associated with preference for sexually conditioned cues thus confirming the relationship between sexual cue conditioning and attentional bias [Banca et al., 2016]. These findings of enhanced activity related to sexually conditioned cues differ from that of the outcome (or the unconditioned stimulus) in which enhanced habituation, possibly consistent with the concept of tolerance, increases the preference for novel sexual stimuli [Banca et al., 2016]. Together these findings help elucidate the underlying neurobiology of CSB leading toward a greater understanding of the disorder and identification of possible therapeutic markers.

26) Ventral Striatum Activity When Watching Preferred Pornographic Pictures is Correlated With Symptoms of Internet Pornography Addiction (2016) - [greater cue reactivity/sensitization] – A German fMRI study. Finding #1: Reward center activity (ventral striatum) was higher for preferred pornographic pictures. Finding #2: Ventral striatum reactivity correlated with the internet sex addiction score. Both findings indicate sensitization and align with the addiction model. The authors state that the "Neural basis of Internet pornography addiction is comparable to other addictions." An excerpt:

One type of Internet addiction is excessive pornography consumption, also referred to as cybersex or Internet pornography addiction. Neuroimaging studies found ventral striatum activity when participants watched explicit sexual stimuli compared to non-explicit sexual/erotic material. We now hypothesized that the ventral striatum should respond to preferred pornographic compared to non-preferred pornographic pictures and that the ventral striatum activity in this contrast should be correlated with subjective symptoms of Internet pornography addiction. We studied 19 heterosexual male participants with a picture paradigm including preferred and non-preferred pornographic material.

Pictures from the preferred category were rated as more arousing, less unpleasant, and closer to ideal. Ventral striatum response was stronger for the preferred condition compared to non-preferred pictures. Ventral striatum activity in this contrast was correlated with the self-reported symptoms of Internet pornography addiction. The subjective symptom severity was also the only significant predictor in a regression analysis with ventral striatum response as dependent variable and subjective symptoms of Internet pornography addiction, general sexual excitability, hypersexual behavior, depression, interpersonal sensitivity, and sexual behavior in the last days as predictors. The results support the role for the ventral striatum in processing reward anticipation and gratification linked to subjectively preferred pornographic material. Mechanisms for reward anticipation in ventral striatum may contribute to a neural explanation of why individuals with certain preferences and sexual fantasies are at-risk for losing their control over Internet pornography consumption.

27) Altered Appetitive Conditioning and Neural Connectivity in Subjects With Compulsive Sexual Behavior (2016) - [greater cue reactivity/sensitization and dysfunctional prefrontal circuits] - This German fMRI study replicated two major findings from Voon et al., 2014 and Kuhn & Gallinat 2014. Main Findings: The neural correlates of appetitive conditioning and neural connectivity were altered in the CSB group. According to the researchers, the first alteration - heightened amygdala activation - might reflect facilitated conditioning (greater "wiring" to previously neutral cues predicting porn images). The second alteration - decreased connectivity between the ventral striatum and the prefrontal cortex - could be a marker for impaired ability to control impulses. Said the researchers, "These [alterations] are in line with other studies investigating the neural correlates of addiction disorders and impulse control deficits." The findings of greater amygdalar activation to cues (sensitization) and decreased connectivity between the reward center and the prefrontal cortex (hypofrontality) are two of the major brain changes seen in substance addiction. In addition, 3 of the 20 compulsive porn users suffered from "orgasmic-erection disorder." An excerpt:

In general, the observed increased amygdala activity and the concurrently decreased ventral striatal-PFC coupling allows speculations about the etiology and treatment of CSB. Subjects with CSB seemed more prone to establish associations between formally neutral cues and sexually relevant environmental stimuli. Thus, these subjects are more likely to encounter cues that elicit approaching behavior. Whether this leads to CSB or is a result of CSB must be answered by future research. In addition, impaired regulation processes, which are reflected in the decreased ventral striatal-prefrontal coupling, might further support the maintenance of the problematic behavior.

28) Compulsivity Across the Pathological Misuse of Drug and Non-Drug Rewards (2016) - [greater cue reactivity/sensitization, enhanced conditioned responses] - This Cambridge University fMRI study compares aspects of compulsivity in alcoholics, binge-eaters, video game addicts and porn addicts (CSB). Excerpts:

In contrast to other disorders, CSB compared to HV showed faster acquisition to reward outcomes along with a greater perseveration in the reward condition irrespective of outcome. The CSB subjects did not show any specific impairments in set shifting or reversal learning. These findings converge with our previous findings of enhanced preference for stimuli conditioned to either sexual or monetary outcomes, overall suggesting enhanced sensitivity to rewards (Banca et al., 2016). Further studies using salient rewards are indicated.

29) Subjective Craving for Pornography and Associative Learning Predict Tendencies Towards Cybersex Addiction in a Sample of Regular Cybersex Users (2016) - [greater cue reactivity/sensitization, enhanced conditioned responses] – This unique study conditioned subjects to formerly neutral shapes, which predicted the appearance of a pornographic image. Excerpts:

There is no consensus regarding the diagnostic criteria of cybersex addiction. Some approaches postulate similarities to substance dependencies, for which associative learning is a crucial mechanism. In this study, 86 heterosexual males completed a Standard Pavlovian to Instrumental Transfer Task modified with pornographic pictures to investigate associative learning in cybersex addiction. Additionally, subjective craving due to watching pornographic pictures and tendencies towards cybersex addiction were assessed. Results showed an effect of subjective craving on tendencies towards cybersex addiction, moderated by associative learning. Overall, these findings point towards a crucial role of associative learning for the development of cybersex addiction, while providing further empirical evidence for similarities between substance dependencies and cybersex addiction. In summary, the results of the current study suggest that associative learning might play a crucial role regarding the development of cybersex addiction. Our findings provide further evidence for similarities between cybersex addiction and substance dependencies since influences of subjective craving and associative learning were shown.

30) Exploring the Relationship between Sexual Compulsivity and Attentional Bias to Sex-Related Words in a Cohort of Sexually Active Individuals (2017) - [greater cue reactivity/sensitization, desensitization] - This study replicates the findings of this 2014 Cambridge University study, which compared the attentional bias of porn addicts to healthy controls. Here's what's new: The study correlated the "years of sexual activity" with 1) the sex addiction scores and also 2) the results of the attentional bias task. Among those scoring high on sexual addiction, fewer years of sexual experience were related to greater attentional bias (explanation of attentional bias). So higher sexual compulsivity scores + fewer years of sexual experience = greater signs of addiction (greater attentional bias, or interference). But attentional bias declines sharply in the compulsive users, and disappears at the highest number of years of sexual experience. The authors concluded that this result could indicate that more years of "compulsive sexual activity" lead to greater habituation or a general numbing of the pleasure response (desensitization). An excerpt from the conclusion:

One possible explanation for these results is that as a sexually compulsive individual engages in more compulsive behaviour, an associated arousal template develops [36–38] and that over time, more extreme behaviour is required for the same level of arousal to be realised. It is further argued that as an individual engages in more compulsive behaviour, neuropathways become desensitized to more ‘normalised’ sexual stimuli or images and individuals turn to more ‘extreme’ stimuli to realise the arousal desired. This is in accordance with work showing that ‘healthy’ males become habituated to explicit stimuli over time and that this habituation is characterised by decreased arousal and appetitive responses [39]. This suggests that more compulsive, sexually active participants have become ‘numb’ or more indifferent to the ‘normalised’ sex-related words used in the present study and as such display decreased attentional bias, while those with increased compulsivity and less experience still showed interference because the stimuli reflect more sensitised cognition

31) Mood changes after watching pornography on the Internet are linked to symptoms of Internet-pornography-viewing disorder (2016) - [greater cravings/sensitization, less liking] - Excerpts:

The main results of the study are that tendencies towards Internet Pornography Disorder (IPD) were associated negatively with feeling generally good, awake, and calm as well as positively with perceived stress in daily life and the motivation to use Internet pornography in terms of excitation seeking and emotional avoidance.  Furthermore, tendencies towards IPD were negatively related to mood before and after watching Internet pornography as well as an actual increase of good and calm mood. The relationship between tendencies towards IPD and excitement seeking due to Internet-pornography use was moderated by the evaluation of the experienced orgasm's satisfaction. Generally, the results of the study are in line with the hypothesis that IPD is linked to the motivation to find sexual gratification and to avoid or to cope with aversive emotions as well as with the assumption that mood changes following pornography consumption are linked to IPD (Cooper et al., 1999 and Laier and Brand, 2014).

32) Problematic sexual behavior in young adults: Associations across clinical, behavioral, and neurocognitive variables (2016) - [poorer executive functioning] - Individuals with Problematic Sexual Behaviors (PSB) exhibited several neuro-cognitive deficits. These findings indicate poorer executive functioning (hypofrontality) which is a key brain feature occurring in drug addicts. A few excerpts:

One notable result from this analysis is that PSB shows significant associations with a number of deleterious clinical factors, including lower self-esteem, decreased quality of life, elevated BMI, and higher comorbidity rates for several disorders…

…it is also possible that the clinical features identified in the PSB group are actually the result of a tertiary variable which gives rise to both PSB and the other clinical features. One potential factor filling this role could be the neurocognitive deficits identified in the PSB group, particularly those relating to working memory, impulsivity/impulse control, and decision making. From this characterization, it is be possible to trace the problems evident in PSB and additional clinical features, such as emotional dysregulation, to particular cognitive deficits…

If the cognitive problems identified in this analysis are actually the core feature of PSB, this may have notable clinical implications.

33) Executive Functioning of Sexually Compulsive and Non-Sexually Compulsive Men Before and After Watching an Erotic Video (2017) - [poorer executive functioning, greater cravings/sensitization] - Exposure to porn affected executive functioning in men with "compulsive sexual behaviors," but not healthy controls. Poorer executive functioning when exposed to addiction-related cues is a hallmark of substance disorders (indicating both altered prefrontal circuits and sensitization). Excerpts:

This finding indicates better cognitive flexibility after sexual stimulation by controls compared with sexually compulsive participants. These data support the idea that sexually compulsive men do not to take advantage of the possible learning effect from experience, which could result in better behavior modification. This also could be understood as a lack of a learning effect by the sexually compulsive group when they were sexually stimulated, similar to what happens in the cycle of sexual addiction, which starts with an increasing amount of sexual cognition, followed by the activation of sexual scripts and then orgasm, very often involving exposure to risky situations.

34) Can Pornography be Addictive? An fMRI Study of Men Seeking Treatment for Problematic Pornography Use (2017) - [greater cue reactivity/sensitization, enhanced conditioned responses] – An fMRI study involving a unique cue-reactivity paradigm where formerly neutral shapes predicted the appearance of pornographic images. Excerpts:

Men with and without problematic porn use (PPU) differed in brain reactions to cues predicting erotic pictures, but not in reactions to erotic pictures themselves, consistent with the incentive salience theory of addictions. This brain activation was accompanied by increased behavioral motivation to view erotic images (higher 'wanting'). Ventral striatal reactivity for cues predicting erotic pictures was significantly related to the severity of PPU, amount of pornography use per week and number of weekly masturbations. Our findings suggest that like in substance-use and gambling disorders the neural and behavioral mechanisms linked to anticipatory processing of cues relate importantly to clinically relevant features of PPU. These findings suggest that PPU may represent a behavioral addiction and that interventions helpful in targeting behavioral and substance addictions warrant consideration for adaptation and use in helping men with PPU.

35) Conscious and Non-Conscious Measures of Emotion: Do They Vary with Frequency of Pornography Use? (2017) - [habituation or desensitization] - Study assessed porn users' responses (EEG readings & Startle Response) to various emotion-inducing images - including erotica. The study found several neurological differences between low frequency porn users and high frequency porn users. Excerpts:

Findings suggest that increased pornography use appears to have an influence on the brain’s non-conscious responses to emotion-inducing stimuli which was not shown by explicit self-report.

4.1. Explicit Ratings: Interestingly, the high porn use group rated the erotic images as more unpleasant than the medium use group. The authors suggest this may be due to the relatively “soft-core” nature of the “erotic” images contained in the IAPS database not providing the level of stimulation that they may usually seek out, as it has been shown by Harper and Hodgins [58] that with frequent viewing of pornographic material, many individuals often escalate into viewing more intense material to maintain the same level of physiological arousal. The “pleasant” emotion category saw valence ratings by all three groups to be relatively similar with the high use group rating the images as slightly more unpleasant on average than the other groups. This may again be due to the “pleasant” images presented not being stimulating enough for the individuals in the high use group. Studies have consistently shown a physiological downregulation in processing of appetitive content due to habituation effects in individuals who frequently seek out pornographic material [3, 7, 8]. It is the authors’ contention that this effect may account for the results observed.

4.3. Startle Reflex Modulation (SRM): The relative higher amplitude startle effect seen in the low and medium porn use groups may be explained by those in the group intentionally avoiding the use of pornography, as they may find it to be relatively more unpleasant. Alternatively, the results obtained also may be due to a habituation effect, whereby individuals in these groups do watch more pornography than they explicitly stated—possibly due to reasons of embarrassment among others, as habituation effects have been shown to increase startle eye blink responses [41, 42].

36) Exposure to Sexual Stimuli Induces Greater Discounting Leading to Increased Involvement in Cyber Delinquency Among Men (2017) - [poorer executive functioning, greater impulsivity - causation experiment] - In two studies exposure to visual sexual stimuli resulted in: 1) greater delayed discounting (inability to delay gratification), 2) greater inclination to engage in cyber-delinquency, 3) greater inclination to purchase counterfeit goods and hack someone's Facebook account. Taken together this indicates that porn use increases impulsivity and may reduce certain executive functions (self-control, judgment, foreseeing consequences, impulse control). Excerpt:

People frequently encounter sexual stimuli during Internet use. Research has shown that stimuli inducing sexual motivation can lead to greater impulsivity in men, as manifested in greater temporal discounting (i.e., a tendency to prefer smaller, immediate gains to larger, future ones).

In conclusion, the current results demonstrate an association between sexual stimuli (e.g., exposure to pictures of sexy women or sexually arousing clothing) and men’s involvement in cyber delinquency. Our findings suggest that men’s impulsivity and self-control, as manifested by temporal discounting, are susceptible to failure in the face of ubiquitous sexual stimuli. Men may benefit from monitoring whether exposure to sexual stimuli is associated with their subsequent delinquent choices and behavior. Our findings suggest that encountering sexual stimuli can tempt men down the road of cyber delinquency

The current results suggest that the high availability of sexual stimuli in cyberspace may be more closely associated with men's cyber-delinquent behavior than previously thought.

37) Predictors for (Problematic) Use of Internet Sexually Explicit Material: Role of Trait Sexual Motivation and Implicit Approach Tendencies Towards Sexually Explicit Material (2017) - [greater cue reactivity/sensitization/cravings] - Excerpts: 

The present study investigated whether trait sexual motivation and implicit approach tendencies toward sexual material are predictors of problematic SEM use and of the daily time spent watching SEM. In a behavioral experiment, we used the Approach-Avoidance Task (AAT) for measuring implicit approach tendencies towards sexual material. A positive correlation between implicit approach tendency towards SEM and the daily time spent on watching SEM might be explained by attentional effects: A high implicit approach tendency can be interpreted as an attentional bias towards SEM. A subject with this attentional bias might be more attracted to sexual cues on the Internet resulting in higher amounts of time spent on SEM sites.

Recent reviews of the literature:

The first two peer-reviewed papers below provide greater context for many of the preceding neurological studies. The first excerpt from Park et al., 2016 explains how internet pornography functions as a powerful and self-reinforcing stimulus (many of the above studies are cited within):

3.3. Internet Pornography Use as Self-Reinforcing Activity

As the reward system encourages organisms to remember and repeat critical behaviors, such as sex, eating, and socializing, chronic Internet pornography use may become a self-reinforcing activity [95]. The reward system is vulnerable to pathological learning [96], particularly in adolescents, such as greater risk of addiction [97, 98] and greater future use of “deviant pornography” (bestiality and child pornography) [99]. Several lines of research have begun to elucidate the overlap in the neural substrates of sexual learning and addiction [100, 101]. For example, sexual behaviors and addictive drugs activate the same sets of neurons within the same reward system structures (NAc, basolateral amygdala, anterior cingulated area) [102]. In contrast, very little overlap exists between other natural rewards (food, water) and addictive drugs, such as cocaine and methamphetamine [102]. Thus, methamphetamine use recruits the same mechanisms and neural substrates as does the natural reward of sexual stimulation [103]. In another study, cocaine addicts had nearly identical brain activation patterns when viewing pornography and cues related to their addiction, but brain activation patterns when viewing nature scenes were completely different [104].

Furthermore, both repeated sexual behaviors and repeated psychostimulant administration induce up regulation of Delta FosB, a transcription factor that promotes several neuroplastic changes that sensitize the mesolimbic dopamine system to the activity in question [103]. In both addictive drug use and sexual reward, this up regulation in the same NAc neurons is mediated via dopamine receptors [103]. This process renders the individual hyper-sensitized to stimuli associated with the activity (increased incentive salience) [105]. Exposure to related cues then triggers cravings to engage in the behavior (increased “wanting”), and may lead to compulsive use [106]. In comparing sexual reward to substances of abuse, researchers Pitchers et al. concluded that, “Natural and drug rewards not only converge on the same neural pathway, they converge on the same molecular mediators, and likely in the same neurons in the NAc, to influence the incentive salience and the “wanting” of both types of rewards” [103]. In the same vein, a 2016 review by Kraus, Voon and Potenza affirmed that, “Common neurotransmitter systems may contribute to [compulsive sexual behavior] and substance use disorders, and recent neuroimaging studies highlight similarities relating to craving and attentional biases” [107].

To date, the potential health risks of Internet pornography are not as well understood as those for alcohol and tobacco use, and Internet pornography use is widely portrayed as both ordinary behavior and increasingly socially acceptable [108,109]. Perhaps this is why men are slow to connect their pornography viewing with their sexual difficulties. After all, “Who doesn’t watch porn these days?” as one of our servicemen asked his physician. He regarded his problematic progression as normal, perhaps even evidence of high libido [110]. However, there is growing evidence that it was an indication of addiction-related processes [31, 52, 54, 73, 86, 107, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122]. Finnish researchers found “adult entertainment” to be the most common reason for compulsive Internet use [123], and a one-year longitudinal study of Internet applications revealed that Internet pornography may have the highest potential for addiction [124], with Internet gaming a close second in both studies. To date, Internet gaming disorder (IGD) has been slated for further study in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) [125], while Internet pornography addiction disorder has not. However, in the view of UK researcher Griffiths, “the empirical base for sex addiction is arguably on a par with IGD” [73]. In fact, various addiction experts are calling for Internet addiction to be recognized as a generalized problem with more specific subtypes such as gaming and pornography [118, 126, 127, 128]. A 2015 review also concluded that Internet pornography addiction should be recognized as a subtype of Internet addiction, which belongs in the DSM [118].

Interestingly, our second serviceman meets many of the criteria proposed for IGD in the DSM-5, adjusted for Internet pornography use. He exhibited the following: (1) preoccupation with Internet pornography; (2) loss of interest in sex with his real-life partner as a consequence; (3) withdrawal symptoms such as irritability and resentment; (4) seeking pornography to relieve his bad feelings; (5) inability to quit despite severe problems; and (6) escalation to more graphic material.

Excerpts from Pornography, Pleasure, and Sexuality: Towards a Hedonic Reinforcement Model of Sexually Explicit Internet Media Use (2017), which explores why internet porn might be particularly reinforcing:

Hedonic Reinforcement

In the second point of the model, we posit that IP serves as a particularly potent reinforcement of hedonic sexual motives. Whereas sexual activity of any kind is likely rewarding on some level, IP presents the potential for a combination of specific, easily obtainable, continually novel, and virtually immediate rewards in a manner that is uniquely and intensely rewarding (e.g., Gola et al., 2016). Many popular, non-empirical works have suggested as much (e.g., Foubert, 2016; Wilson, 2014; Struthers, 2009). Additionally, some limited reviews have considered the possibility that IP represents an abnormally rewarding stimulus (e.g., Barrett, 2010; Hilton, 2013; Grinde, 2002) in the context of human evolution. However, to date, there has been no systematic review examining the possibility that pornography represents an especially powerful hedonic reward. In the following sections, we review evidence for this second step.

Why might IP be particularly reinforcing?

The notion of highly rewarding stimuli has been thoroughly discussed in various literatures for decades. Gambling (Zuckerman & Kuhlman, 2000; Fauth-Buhler, Mann, & Potenza, 2016), narcotics (Nesse & Berridge, 1997), and even video games (Koepp et al., 1998) have all been suggested as extremely rewarding stimuli that exploit evolutionary drives. In each of the aforementioned examples, the behavior (e.g., gambling) exploits an evolutionarily developed drive (e.g., sensation-seeking/risk-taking) and produces an intense reward (e.g., win-loss potential) that directly and instantaneously rewards the drive. Also, as previously discussed, this pattern is particularly well-documented in literature on hunger.

 Hunger is an evolutionarily-selected drive that is necessary for survival (Pinel, Assanand, & Lehman, 2000; van de Pos & Ridder, 2006). Similar to sexual drive, hunger also involves a hedonic component (Lowe & Butrin, 2007). Humans derive pleasure from consuming foods that meet basic biological needs (Mela, 2006). However, humans also have a unique ability to create ever-more-intense rewards for themselves that bypass many of the energy and effort expenditures that would have, historically, been necessary for a drive to be satiated. This is particularly evident in the recent (in human evolution) advent of highly palatable foods. These foods often involve potent combinations of sweet, savory, and salty flavors that are intensely rewarding to evolutionarily developed hunger drives (Gearhardt, Davis, Kuschner, & Brownell, 2011). Over time, the propagation of such foods, alongside the ease with which they are now accessed, both in price and prevalence, have resulted in general cultural changes in food consumptions habits (Drewnowski & Specter, 2004; Hardin-Fanning & Rayens, 2015), more hedonic consumption of food (Monteiro et al., 2013), increased obesity (Gearhardt et al., 2011), and, in extreme cases, patterns of food consumption that seem addictive or compulsive (Gearhardt et al., 2011). Prior works have also suggested similar parallels with problematic IPU (Hall, 2013; Love, Laier, Brand, Hatch, & Hajela, 2015).

Similar to hunger, pornography likely taps into humans evolutionarily derived sexual drive (Malamuth, 1996; Salmon, 2012). Sexual drive is a fundamental human instinct, necessary for the survival of the species. As has been argued elsewhere (e.g., Salmon, 2012), pornography has developed in such a way as to satisfy that drive in a unique way. Specifically, pornography exploits evolutionary drives to pursue fitness and novelty in sexual partners (Salmon, 2012), while still allowing for conservation of effort and energy through minimal social effort. Although sexual media has existed for over a century now, the variety, continuous novelty, availability, and accessibility of IP make it a unique stimulus in the context of human evolution in a way similar to hyperpalatable food. Collectively, these factors point toward a stimulus that is highly and uniquely rewarding to evolutionary derived sexual drives.

Accessibility of IP

For many people, quickly and easily obtained rewards are often rated as being preferable to delayed rewards, even when those delayed rewards may be objectively better (e.g., delayed gratification, delay discounting; Bickel & Marsch, 2001). This is one component of what makes many pleasure-inducing, psychoactive substances habit-forming (e.g., Bickel & Marsch, 2001): Although other factors might contribute to addictive behavior patterns (e.g., physiological dependence, genetic predisposition), the association between stimulus and instant reward can be habit forming. Building on this, prior theoretical work has contended that the instantaneous nature of online technology in general produces rewards of internet behaviors at a rate unprecedented by other, non-chemical stimuli (Davis, 2001).

From the outset, research on IP has repeatedly emphasized the instantaneous nature of the online environment as representing a new and potentially problematic adjustment to the standard rewarding nature of sexually explicit media more generally (Cooper et al., 1998; Schwartz & Southern, 2000). Whereas partnered sexual interaction typically requires social effort and whereas conventional, printed or recorded sexually explicit media required at least some effort and cost to obtain (e.g., driving to and spending money an adult theatre or store), IP is quickly and easily accessible, giving it advantages as a relative reinforcement of a specific behavior for the satisfaction of sexual desire and drive.

IP likely represents a uniquely easy way to obtain sexual gratification that has been previously unprecedented in the context of human evolution. In a previously reviewed qualitative study (Rothman et al., 2015) of inner-city youth, a key theme related to pornography use was the availability and simplicity of access. Additionally, within the same sample, there were also reports of the use IP, in part, due to the ease with which IPU satisfied sexual desires or relieved sexual tension. IP was simply easy to use, which contributed to use patterns. Similarly, in a qualitative study (Löfgren-Mårtenson & Månsson, 2010), of Swedish adolescents (N=73; 49% male; Range 14-20), IPU was described as a quick and relatively easy means of obtaining sexual pleasure and releasing sexual tension. Together, these findings provide some support for the conclusion that one of the unique aspects of the internet is its ability to instantly reward sexual drive and desire.

Reviews with relevant excerpts:

1) Cybersex Addiction (2015). Excerpts:

Many individuals use cybersex applications, particularly Internet pornography. Some individuals experience a loss of control over their cybersex use and report that they cannot regulate their cybersex use even if they experienced negative consequences. In recent articles, cybersex addiction is considered a specific type of Internet addiction. Some current studies investigated parallels between cybersex addiction and other behavioral addictions, such as Internet Gaming Disorder. Cue-reactivity and craving are considered to play a major role in cybersex addiction. Also, neurocognitive mechanisms of development and maintenance of cybersex addiction primarily involve impairments in decision making and executive functions. Neuroimaging studies support the assumption of meaningful commonalities between cybersex addiction and other behavioral addictions as well as substance dependency.

2)  Neuroscience of Internet Pornography Addiction: A Review and Update (2015). A thorough review of the neuroscience literature related to Internet addiction sub-types, with special focus on internet porn addiction. The review also critiques two recent headline-grabbing EEG studies by teams headed by Prause (who claims the findings cast doubt on porn addiction). Excerpts:

Many recognize that several behaviors potentially affecting the reward circuitry in human brains lead to a loss of control and other symptoms of addiction in at least some individuals. Regarding Internet addiction, neuroscientific research supports the assumption that underlying neural processes are similar to substance addiction. The American Psychiatric Association (APA) has recognized one such Internet related behavior, Internet gaming, as a potential addictive disorder warranting further study, in the 2013 revision of their Diagnostic and Statistical Manual. Other Internet related behaviors, e.g., Internet pornography use, were not covered. Within this review, we give a summary of the concepts proposed underlying addiction and give an overview about neuroscientific studies on Internet addiction and Internet gaming disorder. Moreover, we reviewed available neuroscientific literature on Internet pornography addiction and connect the results to the addiction model. The review leads to the conclusion that Internet pornography addiction fits into the addiction framework and shares similar basic mechanisms with substance addiction. Together with studies on Internet addiction and Internet Gaming Disorder we see strong evidence for considering addictive Internet behaviors as behavioral addiction.

3) Sex Addiction as a Disease: Evidence for Assessment, Diagnosis, and Response to Critics (2015), which provides a chart that takes on specific criticisms of porn/sex addiction, offering citations that counter them. Excerpts:

As we continue to face a myriad of individual, family, and societal issues related to addiction, how we treat addiction also has to change. Addiction treatment has come a long way but has a long way yet to go. As seen throughout this article, the common criticisms of sex as a legitimate addiction do not hold up when compared to the movement within the clinical and scientific communities over the past few decades. There is ample scientific evidence and support for sex as well as other behaviors to be accepted as addiction. This support is coming from multiple fields of practice and offers incredible hope to truly embrace change as we better understand the problem. Decades of research and developments in the field of addiction medicine and neuroscience reveal the underlying brain mechanisms involved in addiction. Scientists have identified common pathways affected by addictive behavior as well as differences between the brains of addicted and non-addicted individuals, revealing common elements of addiction, regardless of the substance or behavior. However, there remains a gap between the scientific advances and the understanding by the general public, public policy, and treatment advances.

4) Neurobiology of Compulsive Sexual Behavior: Emerging Science (2016). Excerpts:

Although not included in DSM-5, compulsive sexual behavior (CSB) can be diagnosed in ICD-10 as an impulse control disorder. However, debate exists about CSB’s classification (eg, as an impulsive-compulsive disorder, a feature of hypersexual disorder, an addiction, or along a continuum of normative sexual behavior. Current gaps in research exist complicating definitive determination whether CSB is best considered as an addiction or not…. Additional research is needed to understand how neurobiological features relate to clinically relevant measures like treatment outcomes for CSB. Classifying CSB as a ‘behavioral addiction’ would have significant implications for policy, prevention and treatment efforts….. Given some similarities between CSB and drug addictions, interventions effective for addictions may hold promise for CSB, thus providing insight into future research directions to investigate this possibility directly.

5) Should Compulsive Sexual Behavior be Considered an Addiction? (2016). Excerpt:

With the release of DSM-5, gambling disorder was reclassified with substance use disorders. This change challenged beliefs that addiction occurred only by ingesting of mind-altering substances and has significant implications for policy, prevention and treatment strategies [97]. Data suggest that excessive engagement in other behaviors (e.g. gaming, sex, compulsive shopping) may share clinical, genetic, neurobiological and phenomenological parallels with substance addictions [2,14].

Another area needing more research involves considering how technological changes may be influencing human sexual behaviors. Given that data suggest that sexual behaviors are facilitated through Internet and smartphone applications [98–100], additional research should consider how digital technologies relate to CSB (e.g. compulsive masturbation to Internet pornography or sex chatrooms) and engagement in risky sexual behaviors (e.g. condomless sex, multiple sexual partners on one occasion).

Overlapping features exist between CSB and substance use disorders. Common neurotransmitter systems may contribute to CSB and substance use disorders, and recent neuroimaging studies highlight similarities relating to craving and attentional biases. Similar pharmacological and psychotherapeutic treatments may be applicable to CSB and substance addictions.

6) Neurobiological Basis of Hypersexuality (2016). Excerpt:

Behavioral addictions and in particular hypersexuality should remind us of the fact that addictive behavior actually relies on our natural survival system. Sex is an essential component in survival of species since it is the pathway for reproduction. Therefore it is extremely important that sex is considered pleasurable and has primal rewarding properties, and although it may turn into an addiction at which point sex may be pursued in a dangerous and counterproductive way, the neural basis for addiction might actually serve very important purposes in primal goal pursuit of individuals…. Taken together, the evidence seems to imply that alterations in the frontal lobe, amygdala, hippocampus, hypothalamus, septum, and brain regions that process reward play a prominent role in the emergence of hypersexuality. Genetic studies and neuropharmacological treatment approaches point at an involvement of the dopaminergic system.

7) Compulsive Sexual Behaviour as a Behavioural Addiction: The Impact of the Internet and Other Issues (2016). Excerpts:

I have carried out empirical research into many different behavioural addictions (gambling, video-gaming, internet use, exercise, sex, work, etc.) and have argued that some types of problematic sexual behaviour can be classed as sex addiction, depending upon the definition of addiction used [2-5]….

The paper also appears to have an underlying assumption that empirical research from a neurobiological/genetic perspective should be treated more seriously than from a psychological perspective. Whether problematic sexual behaviour is described as CSB, sex addiction and/or hypersexual disorder, there are thousands of psychological therapists around the world who treat such disorders [7]. Consequently, clinical evidence from those who help and treat such individuals should be given greater credence by the psychiatric community….

Arguably the most important development in the field of CSB and sex addiction is how the internet is changing and facilitating CSB [2, 8, 9]. This was not mentioned until the concluding paragraph, yet research into online sex addiction (while comprising a small empirical base) has existed since the late 1990s, including sample sizes of up to almost 10 000 individuals [10-17]. In fact, there have been recent reviews of empirical data concerning online sex addiction and treatment [4, 5]. These have outlined the many specific features of the internet that may facilitate and stimulate addictive tendencies in relation to sexual behaviour (accessibility, affordability, anonymity, convenience, escape, disinhibition, etc.).

8) Searching for Clarity in Muddy Water: Future Considerations for Classifying Compulsive Sexual Behavior as An Addiction (2016). Excerpts:

We recently considered evidence for classifying compulsive sexual behavior (CSB) as a non-substance (behavioral) addiction. Our review found that CSB shared clinical, neurobiological and phenomenological parallels with substance-use disorders….

Although the American Psychiatric Association rejected hypersexual disorder [4] from DSM-5, a diagnosis of CSB (excessive sex drive) can be made using ICD-10 [13]. CSB is also being considered by ICD-11 [14], although its ultimate inclusion is not certain. Future research should continue to build knowledge and strengthen a framework for better understanding CSB and translating this information into improved policy, prevention, diagnosis, and treatment efforts to minimize the negative impacts of CSB.

9) Integrating Psychological and Neurobiological Considerations Regarding The Development and Maintenance of Specific Internet-Use Disorders: An Interaction of Person-Affect-Cognition-Execution model (2016). A review of the mechanisms underlying the development and maintenance of specific Internet-use disorders, including "Internet-pornography-viewing disorder." The authors suggest that pornography addiction (and cybersex addiction) be classified as internet use disorders and placed with other behavioral addictions under substance-use disorders as addictive behaviors.

Although the DSM-5 focuses on Internet gaming, a meaningful number of authors indicate that treatment-seeking individuals may also use other Internet applications or sites addictively….

From the current state of research, we suggest to include Internet-use disorders in the upcoming ICD-11. It is important to note that beyond Internet-gaming disorder, other types of applications are also used problematically. One approach could involve the introduction of a general term of Internet-use disorder, which could then be specified considering the first-choice application that is used (for example Internet-gaming disorder, Internet-gambling disorder, Internet-pornography-use disorder, Internet-communication disorder, and Internet-shopping disorder).

10) The Neurobiology of Sexual Addiction: Chapter from Neurobiology of Addictions, Oxford Press (2016) - Excerpts:

We review the neurobiological basis for addiction, including natural or process addiction, and then discuss how this relates to our current understanding of sexuality as a natural reward that can become functionally "unmanageable" in an individual's life….

It is clear that the current definition and understanding of addiction has changed based with the infusion of knowledge regarding how the brain learns and desires.  Whereas sexual addiction was formerly defined based solely on behavioral criteria, it is now seen also through the lens of neuromodulation. Those who will not or cannot understand these concepts may continue to cling to a more neurologically naïve perspective, but those who are able to comprehend the behavior in the context of the biology, this new paradigm provides an integrative and functional definition of sexual addiction which informs both the scientist and the clinician.

11) Neuroscientific Approaches to Online Pornography Addiction (2017) – Excerpts:

The availability of pornographic material has substantially increased with the development of the Internet. As a result of this, men ask for treatment more often because their pornography consumption intensity is out of control; i.e., they are not able to stop or reduce their problematic behavior although they are faced with negative consequences…. In the last two decades, several studies with neuroscientific approaches, especially functional magnetic resonance imaging (fMRI), were conducted to explore the neural correlates of watching pornography under experimental conditions and the neural correlates of excessive pornography use. Given previous results, excessive pornography consumption can be connected to already known neurobiological mechanisms underlying the development of substance-related addictions.

Finally, we summarized the studies, which investigated the correlates of excessive pornography consumption on a neural level. Despite a lack of longitudinal studies, it is plausible that the observed characteristics in men with sexual addiction are the results not the causes of excessive pornography consumption. Most of the studies report stronger cue reactivity in the reward circuit toward sexual material in excessive pornography users than in control subjects, which mirrors the findings of substance-related addictions (see review by Chase et al. 2011; Garrison and Potenza 2014). The results concerning a reduced prefrontal-striatal-connectivity in subjects with pornography addiction can be interpreted as a sign of an impaired cognitive control over the addictive behavior. Although all neurobiological insights from these studies support the concept of a pornography addiction, there are still many open questions. To name only a few: Is tolerance a necessary precondition of pornography addiction? Is a change in the preferred sexual material for example toward more deviant material a sign of development of tolerance? Is an increasing time spent on pornography an indicator of tolerance? Are symptoms of withdrawal observable in all subjects considered to be pornography addicted? Are therapeutic interventions known from substance related addictions successfully transferable to pornography addiction? All these questions must be addressed in future research to further answer the question whether the conceptualization of pornography overuse as an addiction is appropriate or not.

12) Is excessive sexual behaviour an addictive disorder? (2017) - Excerpts:

Compulsive sexual behaviour disorder (operationalised as hypersexual disorder) was considered for inclusion in DSM-5 but ultimately excluded, despite the generation of formal criteria and field trial testing.2 This exclusion has hindered prevention, research, and treatment efforts, and left clinicians without a formal diagnosis for compulsive sexual behaviour disorder.

research into the neurobiology of compulsive sexual behaviour disorder has generated findings relating to attentional biases, incentive salience attributions, and brain-based cue reactivity that suggest substantial similarities with addictions.4 Compulsive sexual behaviour disorder is being proposed as an impulse-control disorder in ICD-11, consistent with a proposed view that craving, continued engagement despite adverse consequences, compulsive engagement, and diminished control represent core features of impulse-control disorders.5 This view might have been appropriate for some DSM-IV impulse-control disorders, specifically pathological gambling. However, these elements have long been considered central to addictions, and in the transition from DSM-IV to DSM-5, the category of Impulse Control Disorders Not Elsewhere Classified was restructured, with pathological gambling renamed and reclassified as an addictive disorder.2 At present, the ICD-11 beta draft site lists the impulse-control disorders, and includes compulsive sexual behaviour disorder, pyromania, kleptomania, and intermittent explosive disorder.3

Compulsive sexual behaviour disorder seems to fit well with non-substance addictive disorders proposed for ICD-11, consistent with the narrower term of sex addiction currently proposed for compulsive sexual behaviour disorder on the ICD-11 draft website.3 We believe that classification of compulsive sexual behaviour disorder as an addictive disorder is consistent with recent data and might benefit clinicians, researchers, and individuals suffering from and personally affected by this disorder.

Behavioral addictions, the DSM, the ICD:

But ‘porn addiction’ isn’t in the APA's DSM-5, right? The American Psychiatric Association (APA) has so far dragged its feet on including addictive/compulsive porn use in its diagnostic manual. When it last updated the manual in 2013 (DSM-5), it didn’t formally consider “internet porn addiction,” opting instead to debate “hypersexual disorder.” The latter umbrella term for problematic sexual behavior was recommended for inclusion by the DSM-5’s own Sexuality Work Group after years of review. However, in an eleventh-hour “star chamber” session (according to a Work Group member), other DSM-5 officials unilaterally rejected hypersexuality, citing reasons that have been described as illogical.

In reaching this position, the DSM-5 disregarded formal evidence, widespread reports of the signs, symptoms and behaviors consistent with compulsion and addiction from sufferers and their clinicians, and the formal recommendation of thousands of medical and research experts at the American Society of Addiction Medicine. In 2011 ASAM had generated an extensive Public Policy Statement with FAQs, stating unequivocally that sexual behaviour addictions are real and that addiction is a primary disorder indicating underlying brain changes. From the ASAM FAQs:

QUESTION: This new definition of addiction refers to addiction involving gambling, food, and sexual behaviours. Does ASAM really believe that food and sex are addicting?

ANSWER: The new ASAM definition makes a departure from equating addiction with just substance dependence, by describing how addiction is also related to behaviours that are rewarding. ... This definition says that addiction is about functioning and brain circuitry and how the structure and function of the brains of persons with addiction differ from the structure and function of the brains of persons who do not have addiction. ... Food and sexual behaviours and gambling behaviours can be associated with the ‘pathological pursuit of rewards’ described in this new definition of addiction

Incidentally, the DSM has earned a distinguished critic, Thomas Insel, then Director of the National Institute of Mental Health, who objected to its approach of ignoring underlying physiology and medical theory to ground its diagnoses solely in symptoms. The latter permits erratic, political decisions that defy reality. For example, the DSM once incorrectly classified homosexuality as a mental disorder.

Just prior to the DSM-5’s publication in 2013, Insel warned that it was time for the mental health field to stop relying on the DSM. Its "weakness is its lack of validity," he explained, and "we cannot succeed if we use DSM categories as the "gold standard." He added, "That is why NIMH will be re-orienting its research away from DSM categories." In other words, the NIMH planned to stop funding research based on DSM labels (and their absence).

Since the DSM-5’s publication, hundreds more internet addiction and internet gaming addiction studies, and dozens of neurological studies on porn users have come out. The vast majority continue to undercut the DSM-5’s position. Incidentally, despite media attention to the DSM-5’s stance, practitioners who work with those with problematic sexual behaviors have continued to diagnose such problems. They employ another diagnosis in the DSM-5 as well as one from the current ICD-10, the World Health Organization’s widely used diagnostic manual, the International Classification of Diseases. As pointed out in this 2016 journal article by Dr. Richard Krueger:

Diagnoses that could refer to compulsive sexual behavior have been included in the DSM and ICD for years and can now be diagnosed legitimately in the United States using both DSM-5 and the recently mandated ICD-10 diagnostic coding. Compulsive sexual behavior disorder is being considered for ICD-11.

Krueger is an associate clinical professor of psychiatry at Columbia University’s College of Physicians and Surgeons, and helped revise the sexual disorders section of the DSM-5.

Again, the big news is that The World Health Organization appears poised to set right the APA’s excessive caution. The next edition of its diagnostic manual, the ICD, is due out in 2018. The beta draft of the new ICD-11 includes a diagnosis for “Compulsive Sexual Behavior Disorder” as well as one for “Disorders due to addictive behaviors.” The latter will include "Gambling Disorder" and "Gaming Disorder."

As for the 2013 version of DSM-5, it has recognized behavioral addictions by placing "Gambling disorder" in the Substance-Related and Addictive Disorders. Furthermore, preliminary criteria for "Internet Gaming Disorder" have now been defined in the manual. This 2017 commentary - Addiction Beyond Substances—What's Up with the DSM? - highlights the inconsistencies and misguided logic used by the American Psychiatric Association (APA) in the DSM-5, particularly in regards to their handling of the phenomenon of addictive behaviors related to Internet use. A few excerpts:

We continue to be concerned about the Diagnostic & Statistical Manual of Mental Disorders, Version 5 (DSM-5) remaining a standard in psychological or psychiatric assessments as it contains inconsistencies, contradictions, and perpetuation of focus on diagnostic nomenclature that is out of step with the current research and practice, especially in the field of Addiction Medicine.....

ASAM clearly stated that all aspects of addiction are about common problems in the brain circuits, not the differences in substance(s) or content or behavior(s) (ASAM, 2011). Thus, based on expert opinion and the findings reviewed within the Love et al. (2015) paper, it is illogical that the APA explicitly disavowed some pathological Internet behaviors while allowing others. This decision and statement is neither logically sound, nor consistent with existing and emerging scientific evidence. By this logic, viewing IP excessively and playing Internet games excessively are substantively different, despite substantial overlap in activation of the reward system of the brain, and despite the potential for the exhibition of similar psychosocial behaviors and psychosocial consequences. This is, “biologically and behaviorally inconsistent” (Hilton, 2013).

The misunderstanding of addiction neuroscience can be further seen in the DSM-5’s Diagnostic Features section for IGD wherein they referenced group and team aspects as key features of the disorder. By this logic, abusing substances in a bar or at a party can constitute substance abuse, but abusing substances while alone does not. To make an Internet-related analogy, this logic dictates that someone playing World of Warcraft excessively is addicted, but someone playing Candy Crush excessively is not. The APA’s dismissal of established science in favor of opinions is what appears to have led the NIMH to move away from basing research on DSM categories, and instead to substitute their own more scientifically based research standards (Insel et al., 2013).

We urge the research and treatment communities to be more rigorous and consistent so the populations affected by addiction receive better, more holistic assessments that would guide better treatment and follow-up in the context of addiction as a chronic disease rather than the current focus on one or more behavioral disorders that may or may not be controlled, while other aspects of addiction remain unaddressed.

Unsupported assertions:

Unfortunately, I must address the claims put forth by former UCLA researcher Nicole Prause. In various comments, articles and tweets Prause has claimed that not only did Prause et al., 2015 falsify "a core tenet of the addiction model, the cue reactivity biomarker," but that "a series of behavioral studies replicated by independent laboratories [falsify] other predictions of the addiction model."

Prause cites the content of her 2016 “Letter to the editor” as evidence for the above claims: "Prause et al. (2015) the latest falsification of addiction predictions. Put simply, Prause has gathered all her debunking eggs into one basket - a single paragraph at the end of her letter defending the methodologies and interpretations of Prause et al., 2015. The following analysis of Prause’s “Letter to the editor” serves as a debunking of the debunker's  favorite "eggs": Critique of: Letter to the editor “Prause et al. (2015) the latest falsification of addiction predictions" (2016).

In short, there are no studies that “falsify porn addiction.” This page lists all the studies assessing the brain structure and functioning of internet porn users. To date, every study offers support for the porn addiction model (including Prause's two EEG studies listed earlier: 1) Steele et al., 2013, 2) Prause et al., 2015.

It’s important to note that only one of the studies Prause cited in her “Letter to the editor” had subjects who met the criteria for porn addiction. You read that right. Of all the studies cited, only one contained a group of porn addicts, and 71% of those subjects reported severe negative effects. Bottom line: You cannot falsify "porn addiction" if the studies you cite don't investigate subjects who would be assessed as porn addicts using standard criteria.

More importantly, Prause’s criteria for falsification either have nothing to do with porn addiction or her references have nothing to do with her proposed criteria. For example, Prause‘s letter claimed that "erectile dysfunction is the most common negative consequence of porn use." This is a straw man argument as no peer-reviewed paper has ever claimed that erectile dysfunction is the #1 consequence of porn use. In addition this claim limits itself to the consequences of porn use, which is not the same as the consequences of porn addiction. In another example, Prause claimed that porn addicts simply have a "high sex drive." First, the claim that porn and sex addicts simply have "high sexual desire" has been contradicted by 24 recent studies. Second, she cited her own study (Steele et al., 2013) as support, yet it actually found that porn users with greater cue-reactivity to porn had less desire for sex with a partner. Third, in a 2013 interview Prause admitted that many of the Steele et al. subjects experienced only minor problems (which means they were not porn addicts).

Since Prause claims her two EEG studies “debunk porn addiction” let’s examine what Prause claimed, what the studies really reported, and what other peer-reviewed papers say about the studies.

First, the two Prause studies (Prause et al., 2015, Steele et al., 2013.) involved the same subjects. A major flaw in the Prause studies is that no one knows which, if any, of Prause's subjects met objective criteria for porn addiction. The subjects were recruited from Pocatello, Idaho via online advertisements requesting people who were "experiencing problems regulating their viewing of sexual images.” Pocatello, Idaho is over 50% Mormon, so many of the subjects may have felt that any amount of porn use is a serious problem. Thus, the so-called “porn addicts” were not necessarily addicts, as they were never assessed for porn addiction. Make no mistake, neither Steele et al., 2013 nor Prause et al., 2015 described these 55 subjects as porn addicts or even compulsive porn users. Confirming the mixed nature of her subjects, Prause admitted in 2013 interview that some of the 55 subjects experienced only minor problems (which means they were not porn addicts):

"This study only included people who reported problems, ranging from relatively minor to overwhelming problems, controlling their viewing of visual sexual stimuli."

Thus, neither study can legitimately be used to "falsify" anything to do with addiction.

Besides not establishing which of the subjects were addicted to porn, the Prause studies did not screen subjects for mental disorders, compulsive behaviors, or other addictions. This is critically important for any "brain study" on addiction, lest confounds render results meaningless. Another fatal flaw is that the Prause study subjects were not heterogeneous. They were men and women, including 7 non-heterosexuals, but were all shown standard, possibly uninteresting, male+female porn. This alone discounts any findings. Why? Study after study confirms that men and women have significantly different brain responses to sexual images or films. This is why serious addiction researchers match subjects carefully.

Second, as a group, the subjects "experiencing problems regulating their viewing of sexual images” were desensitized or habituated to vanilla porn, which is consistent with predictions of the addiction model. Here's what each study actually reported about the subjects:

  1. Steele et al., 2013: Individuals with greater cue-reactivity to porn had less desire for sex with a partner, but not less desire to masturbate.
  2. Prause et al., 2015: The more frequent porn users had less brain activation to static images of vanilla porn. Lower EEG readings mean that the "porn addicted" subjects were paying less attention to the pictures. 

A clear pattern emerges from the two studies: The "problematic porn users" were desensitized or habituated to vanilla porn, and those with greater cue-reactivity to porn preferred to masturbate to porn than have sex with a real person. Put simply they were desensitized (a common indication of addiction) and preferred artificial stimuli to a very powerful natural reward (partnered sex). There is no way to interpret these results as falsifying porn addiction.

Prause has also misrepresented the findings of her own studies to the media (which is the primary reason this website has been obliged to critique Prause's studies/claims). As examples, here are a few of the claims surrounding Steele et al., 2013 and Prause et al., 2015.

Steele et al., 2013: Prause, as the Steele et al. spokesperson, claimed that her subjects' brain response differed from other types of addicts (cocaine was the example). A few interviews of Prause:

TV interview:

Reporter: "They were shown various erotic images, and their brain activity monitored."

Prause: "If you think sexual problems are an addiction, we would have expected to see an enhanced response, maybe, to those sexual images. If you think it's a problem of impulsivity, we would have expected to see decreased responses to those sexual images. And the fact that we didn't see any of those relationships suggests that there's not great support for looking at these problem sexual behaviors as an addiction."

Psychology Today interview:

What was the purpose of the study?

Prause: Our study tested whether people who report such problems look like other addicts from their brain responses to sexual images. Studies of drug addictions, such as cocaine, have shown a consistent pattern of brain response to images of the drug of abuse, so we predicted that we should see the same pattern in people who report problems with sex if it was, in fact, an addiction.

Does this prove sex addiction is a myth?

Prause: If our study is replicated, these findings would represent a major challenge to existing theories of sex “addiction.” The reason these findings present a challenge is that it shows their brains did not respond to the images like other addicts to their drug of addiction.

The above claims that subjects' "brains did not respond like other addicts" is not true, and is nowhere to be found in the actual study. It's only found in Prause's interviews. In Steele et al., 2013, the subjects had higher EEG (P300) readings when viewing sexual images, which is exactly what occurs when addicts view images related to their addiction (as in this study on cocaine addicts). Commenting under the Psychology Today interview of Prause, senior psychology professor emeritus John A. Johnson said:

"My mind still boggles at the Prause claim that her subjects' brains did not respond to sexual images like drug addicts' brains respond to their drug, given that she reports higher P300 readings for the sexual images. Just like addicts who show P300 spikes when presented with their drug of choice. How could she draw a conclusion that is the opposite of the actual results?

Dr. Johnson, who had no opinion on sex addiction, commented a second time under the Prause interview:

Mustanski asks, "What was the purpose of the study?" And Prause replies, "Our study tested whether people who report such problems [problems with regulating their viewing of online erotica] look like other addicts from their brain responses to sexual images."

(Said Johnson) But the study did not compare brain recordings from persons having problems regulating their viewing of online erotica to brain recordings from drug addicts and brain recordings from a non-addict control group, which would have been the obvious way to see if brain responses from the troubled group look more like the brain responses of addicts or non-addicts...

Five peer-reviewed papers have since exposed the truth about the lack of support for Prause's claims about her team's work:

  1. ‘High Desire’, or ‘Merely’ An Addiction? A Response to Steele et al. (2014), by Donald L. Hilton, Jr., MD
  2. Neural Correlates of Sexual Cue Reactivity in Individuals with and without Compulsive Sexual Behaviours (2014), by Valerie Voon, Thomas B. Mole, Paula Banca, Laura Porter, Laurel Morris, Simon Mitchell, Tatyana R. Lapa, Judy Karr, Neil A. Harrison, Marc N. Potenza, and Michael Irvine
  3. Neuroscience of Internet Pornography Addiction: A Review and Update (2015), by Todd Love, Christian Laier, Matthias Brand, Linda Hatch & Raju Hajela
  4. Is Internet Pornography Causing Sexual Dysfunctions? A Review with Clinical Reports (2016), by Brian Y. Park, Gary Wilson , Jonathan Berger, Matthew Christman, Bryn Reina, Frank Bishop, Warren P. Klam and Andrew P. Doan
  5. Conscious and Non-Conscious Measures of Emotion: Do They Vary with Frequency of Pornography Use? (2017) by Sajeev Kunaharan, Sean Halpin, Thiagarajan Sitharthan, Shannon Bosshard, and Peter Walla

2) Prause et al. 2015:

In her first unsupported claim Prause boldly publicized on her SPAN lab website, proclaiming that her solitary study "debunks porn addiction":

 

 

 

 

 

What researcher would ever claim to debunk a well established field of research and to refute all previous studies with a single EEG study?

Nicole Prause also claimed her study contained 122 subjects (N). In reality, the study had only 55 "compulsive porn users." The other 67 participants were controls, not subjects.

In a third dubious claim, Prause, et al. stated in both the abstract and in the body of the study:

"These are the first functional physiological data of persons reporting VSS regulation problems."

This is clearly not the case, as the Cambridge fMRI study was published nearly a year earlier.

Because Prause et al., 2015 reported less brain activation to vanilla porn (pictures) related to greater porn use, it is listed above as supporting the hypothesis that chronic porn use down regulates sexual arousal. Put simply, chronic porn users were bored by static images of ho-hum porn (its findings parallel Kuhn & Gallinat., 2014). These findings are consistent with tolerance, a sign of addiction. Tolerance is defined as a person’s diminished response to a drug or stimulus that is the result of repeated use. Six peer-reviewed papers agree that this study actually found desensitization/habituation in frequent porn users

  1. Decreased LPP for sexual images in problematic pornography users may be consistent with addiction models. Everything depends on the model (Commentary on Prause, Steele, Staley, Sabatinelli, & Hajcak, 2015)
  2. Neuroscience of Internet Pornography Addiction: A Review and Update (2015)
  3. Neurobiology of Compulsive Sexual Behavior: Emerging Science (2016)
  4. Should compulsive sexual behavior be considered an addiction? (2016)
  5. Is Internet Pornography Causing Sexual Dysfunctions? A Review with Clinical Reports (2016)
  6. Conscious and Non-Conscious Measures of Emotion: Do They Vary with Frequency of Pornography Use? (2017)

The author of the first critique, neuroscientist Mateusz Gola, summed up it up nicely:

"Unfortunately the bold title of Prause et al. (2015) article has already had an impact on mass media, thus popularizing a scientifically unjustified conclusion."

A bit of investigation exposes contradictory claims about both studies. In Steele et al., 2013 and a blog post about Steele et al. Prause states that less brain activation (the findings of Prause et al., 2015) would indicate habituation or addiction.

In 2013 Prause claimed that Steele et al. was the first time EEG readings were recorded for so-called "hypersexuals." Since this was a "first" Prause admits it's pure speculation as to whether "hypersexuals" should have higher or lower EEG readings than healthy control subjects:

"Given that this is the first time ERPs were recorded in hypersexuals, and literature on addiction (higher P300) and impulsivity (lower P300) suggest opposite predictions, the direction of the hypersexual effect was specified mainly on theoretical grounds." [That is, without much basis at all.]

As explained here Steele et al. 2013 had no control group, so Prause could not compare "porn addicts'" EEG readings to "non-addicts." As a result, her 2013 study told us nothing about the EEG readings for either healthy individuals or "hypersexuals." Let's continue with Prause's views from 2013:

"Therefore, individuals with high sexual desire could exhibit large P300 amplitude difference between sexual stimuli and neutral stimuli due to salience and emotional content of the stimuli. Alternatively, little or no P300 amplitude difference could be measured due to habituation to visual sexual stimuli (VSS)."

In 2013, Prause said that porn addicts, when compared to controls, could exhibit:

  1. higher EEG readings due to cue-reactivity to images, or 
  2. lower EEG readings due to habituation to porn (VSS).

Five months before Steele et al. 2013 was published, Prause and David Ley teamed up to write this Psychology Today blog post about her upcoming study. In it they claim that "diminished electrical response" would indicate habituation or desensitization:

But, when EEG’s were administered to these individuals, as they viewed erotic stimuli, results were surprising, and not at all consistent with sex addiction theory. If viewing pornography actually was habituating (or desensitizing), like drugs are, then viewing pornography would have a diminished electrical response in the brain. In fact, in these results, there was no such response. Instead, the participants’ overall demonstrated increased electrical brain responses to the erotic imagery they were shown, just like the brains of “normal people”...

So, we have 2013 Prause saying "diminished electrical response" would indicate habituation or desensitization (suggesting addiction). Two years later, in 2015, when Prause found evidence of desensitization (common in addicts), she is telling us "diminished electrical response" debunks porn addiction. Huh?

In the intervening two years it took Prause to compare her same tired subject data with an actual control group, she has done a complete flip-flop. Now, she claims the evidence of desensitization/habituation that she found when she added the control group isn't evidence of addiction (which she claimed in 2013 it would have been). Instead, once again, she insists she has "disproved addiction." This is inconsistent and unscientific, and suggests that regardless of opposing findings, she has determined to claim to have "disproven addiction."


SLIDE 19

How do scientists measure the underlying brain changes? Brain scans of various types. These particular scans show reduced pleasure response in drug addicts. These and several other changes have also been seen in gambling addicts, food addicts, and very recently, video game addicts.

ORIGINAL SUPPORT:

The picture for slide 19 came from Drug Addiction and Its Underlying Neurobiological Basis: Neuroimaging Evidence for the Involvement of the Frontal Cortex (2002). The phrase "reduced pleasure response" means desensitization, which can be defined as decreased reward sensitivity. This addiction-related brain change involves long-term chemical and structural changes that leave the addict less sensitive to pleasure. Desensitization often manifests as tolerance, which is the need for a higher dose or greater stimulation to achieve the same response.

The following sections contain hundreds of neurological studies supporting my claim that, “These and several other changes have also been seen in gambling addicts, food addicts, and very recently, video game addicts”:

UPDATED SUPPORT:

The above 3 sections fully support the claims put forth in slide 19.  Slide 18 provides empirical support for these same brain changes occurring in porn addicts. The next slide provides empirical support for addiction-related brain changes occurring in internet and video game addicts.


SLIDE 20

And now, in Internet addicts. I apologize for filling the slide with brain studies – but I want everyone to know they exist. Just notice the dates – these are hot off the press. So far, all brain research points in only one direction: Constant novelty-at-a-click can cause addiction. We know this, because when scientists examined former Internet addicts, these brain changes were reversing themselves. Unfortunately, none of these studies isolate Internet porn users—although they do include them.

Here’s the game changer....

ORIGINAL SUPPORT:

Every study listed on slide 20 reported brain changes in internet addicts that mirrored those found in substance addicts (there were more than 10 studies but that's all I could fit onto one slide). Here is a list of neurological studies on internet addicts' brains published prior to The Great Porn Experiment. Without exception, these studies reported brain changes in internet addicts consistent with the addiction model.

  1. Evidence for striatal dopamine release during a video game (1998)
  2. Dopamine genes and reward dependence in adolescents with excessive internet video game play (2007)
  3. Specific cue reactivity on computer game related cues in excessive gamers (2007)
  4. Influence of excessive internet use on auditory event-related potential (2008)
  5. Brain activities associated with gaming urge of online gaming addiction (2008).
  6. The effect of excessive internet use on N400 event-related potentials (2008)
  7. The effect of methylphenidate on Internet video game play in children with attention deficit hyperactivity disorder (2009)
  8. Decision-making and prepotent response inhibition functions in excessive internet users (2009)
  9. Gray Matter Abnormalities In Internet Addiction: A Voxel-Based Morphometry Study (2009)
  10. Effect of excessive Internet use on the time–frequency characteristic of EEG (2009)
  11. Computer and video game addiction-a comparison between game users and non-game users (2010)
  12. Bupropion sustained release treatment decreases craving for video games and cue-induced brain activity in patients with Internet video game addiction (2010)
  13. Altered regional cerebral glucose metabolism in internet game overusers: a 18F-fluorodeoxyglucose positron emission tomography study (2010)
  14. Changes in Cue Induced Prefrontal Cortex Activity with Video Game Play (2010)
  15. An event-related potential investigation of deficient inhibitory control in individuals with pathological Internet use (2010)
  16. Impulse inhibition in people with Internet addiction disorder: electrophysiological evidence from a Go/NoGo study (2010)
  17. Differentiation of Internet addiction risk level based on autonomic nervous responses: the Internet-addiction hypothesis of autonomic activity (2010)
  18. Increased regional homogeneity in internet addiction disorder a resting state functional magnetic resonance imaging study (2010)
  19. The research of event-related potentials in working memory of the juvenile internet addiction (2010)
  20. Reduced Striatal Dopamine D2 Receptors in People With Internet Addiction (2011)
  21. Microstructure Abnormalities in Adolescents with Internet Addiction Disorder. (2011)
  22. Preliminary study of Internet addiction and cognitive function in adolescents based on IQ tests (2011)
  23. P300 change and cognitive behavioral therapy in subjects with Internet addiction disorder: A 3 month follow-up study (2011)
  24. Male Internet addicts show impaired executive control ability evidence from a color-word: Stroop task (2011)
  25. Deficits in Early-Stage Face Perception in Excessive Internet Users (2011)
  26. Brain correlates of craving for online gaming under cue exposure in subjects with Internet gaming addiction and in remitted subjects. (2011)
  27. Cue induced positive motivational implicit response in young adults with internet gaming addiction (2011)
  28. Enhanced Reward Sensitivity and Decreased Loss Sensitivity in Internet Addicts: An fMRI Study During a Guessing Task (2011)
  29. Brain activity and desire for Internet video game play (2011)
  30. Excessive Internet gaming and decision making: Do excessive World of Warcraft players have problems in decision making under risky conditions? (2011)
  31. The neural basis of video gaming (2011)
  32. Influence of dopaminergic system on internet addiction (2011)
  33. Effects of electroacupuncture combined psycho-intervention on cognitive function and event related potentials P300 and mismatch negativity in patients with internet addiction (2012)
  34. Abnormal White Matter Integrity in Adolescents with Internet Addiction Disorder: A Tract-Based Spatial Statistics Study (2012)
  35. Reduced Striatal Dopamine Transporters in People with Internet Addiction Disorder (2012)

Slide 20 also said that a few internet addiction studies had documented the reversal of addiction-related symptoms and addiction-related brain changes. The following studies supported this claim:

  1. Effects of electroacupuncture combined psycho-intervention on cognitive function and event related potentials P300 and mismatch negativity in patients with internet addiction (2012) - After 40 days of reducing internet use and treatments scored better on cognitive tests, with corresponding EEG changes.
  2. P300 change and cognitive behavioral therapy in subjects with Internet addiction disorder: A 3 month follow-up study (2011) – Altered EEG readings (indicating cognitive deficits) returned to normal levels after 3 months of treatments.
  3. Brain correlates of craving for online gaming under cue exposure in subjects with Internet gaming addiction and in remitted subjects (2011) – The brains of remitted internet addicts responded differently than the brains of current internet addicts.
  4. Online communication, compulsive internet use, and psychosocial well-being among adolescents: A longitudinal study (2008) – Longitudinal study: “Instant messenger use and chatting in chat rooms were positively related to compulsive Internet use and depression 6 months later.”
  5. Precursor or Sequela: Pathological Disorders in People with Internet Addiction Disorder (2011) - The unique aspect is that the research subjects had not used the internet prior to enrolling in college. The study followed first year university students to ascertain what percentage develop internet addiction, and what risk factors may be in play. After one year of school a small percentage were classified as internet addicts. Those who developed internet addiction were initially higher on the obsessive scale, yet lower on scores for anxiety depression, and hostility. An excerpt: "After developing Internet addiction significantly higher scores were observed for depression, anxiety, hostility, interpersonal sensitivity, and psychoticism, suggesting that these were outcomes of Internet addiction disorder. We cannot find a solid pathological predictor for Internet addiction disorder. Internet addiction disorder may bring some pathological problems to the addicts in some ways."
  6. Effect of Pathological Use of the Internet on Adolescent Mental Health (2010) - A prospective study: “Results suggested that young people who are initially free of mental health problems but use the Internet pathologically could develop depression as a consequence.”

UPDATED SUPPORT:

Many more studies have been published since The Great Porn Experiment. Without exception, all have reported brain changes in Internet addicts consistent with the addiction model:

  1. Abnormal brain activation of adolescent internet addict in a ball-throwing animation task: Possible neural correlates of disembodiment revealed by fMRI (2012)
  2. Impaired inhibitory control in internet addiction disorder: A functional magnetic resonance imaging study. (2012)
  3. The effect of family therapy on the changes in the severity of on-line game play and brain activity in adolescents with on-line game addiction (2012)
  4. Attentional bias and disinhibition toward gaming cues are related to problem gaming in male adolescents. (2012)
  5. Alterations in regional homogeneity of resting state brain activity in internet gaming addicts. (2012)
  6. Error processing and response inhibition in excessive computer game players: an event-related potential study (2012)
  7. The brain activations for both cue-induced gaming urge and smoking craving among subjects comorbid with Internet gaming addiction and nicotine dependence. (2012)
  8. Brain fMRI study of crave induced by cue pictures in online game addicts (male adolescents) (2012)
  9. Differential regional gray matter volumes in patients with on-line game addiction and professional gamers (2012)
  10. Diffusion tensor imaging reveals thalamus and posterior cingulate cortex abnormalities in internet gaming addicts (2012).
  11. A voxel based morphometric analysis of brain gray matter in online game addicts (2012)
  12. Cognitive biases toward Internet game-related pictures and executive deficits in individuals with an Internet game addiction (2012)
  13. Cortical Thickness Abnormalities in Late Adolescence with Online Gaming Addiction (2013)
  14. Cue reactivity and its inhibition in pathological computer game players (2013)
  15. Decreased functional brain connectivity in adolescents with internet addiction (2013)
  16. Gray matter and white matter abnormalities in online game addiction (2013).
  17. Cognitive flexibility in internet addicts: fMRI evidence from difficult-to-easy and easy-to-difficult switching situations (2013)
  18. Altered default network resting-state functional connectivity in adolescents with internet gaming addiction (2013)
  19. Reduced orbitofrontal cortical thickness in male adolescents with internet addiction (2013)
  20. Reward/punishment sensitivities among internet addicts: Implications for their addictive behaviors (2013).
  21. Amplitude of low frequency fluctuation abnormalities in adolescents with online gaming addiction (2013)
  22. Just watching the game ain't enough: striatal fMRI reward responses to successes and failures in a video game during active and vicarious playing (2013)
  23. What makes Internet addicts continue playing online even when faced by severe negative consequences? Possible explanations from an fMRI study (2013)
  24. Voxel-level comparison of arterial spin-labeled perfusion magnetic resonance imaging in adolescents with internet gaming addiction (2013).
  25. Brain activation for response inhibition under gaming cue distraction in internet gaming disorder (2013)
  26. Internet gaming addiction: current perspectives (2013)
  27. Comparison of Psychological Symptoms and Serum Levels of Neurotransmitters in Shanghai Adolescents with and without Internet Addiction Disorder: A Case-Control Study (2013)
  28. Resting-state beta and gamma activity in Internet addiction (2013)
  29. Electroencephalographic (EEG) brainmap patterns in a clinical sample of adults diagnosed with an internet addiction (2013)
  30. Impaired Error-Monitoring Function in People with Internet Addiction Disorder: An Event-Related fMRI Study (2013).
  31. Effects of Internet Addiction on Heart Rate Variability in School-Aged Children (2013)
  32. An Error-Related Negativity Potential Investigation of Response Monitoring Function in Individuals with Internet Addiction Disorder (2013)
  33. Decreased frontal lobe function in people with Internet addiction disorder (2013)
  34. Differential resting-state EEG patterns associated with comorbid depression in Internet addiction (2014)
  35. Brains online: structural and functional correlates of habitual Internet use (2014)
  36. Impaired frontal-Basal Ganglia connectivity in adolescents with internet addiction (2014)
  37. Prefrontal Control and Internet Addiction A Theoretical Model and Review of Neuropsychological and Neuroimaging Findings (2014)
  38. Neural responses to various rewards and feedback in the brains of adolescent Internet addicts detected by functional magnetic resonance imaging (2014)
  39. Internet addictive individuals share impulsivity and executive dysfunction with alcohol-dependent patients (2014)
  40. Disrupted Brain Functional Network in Internet Addiction Disorder: A Resting-State Functional Magnetic Resonance Imaging Study (2014)
  41. Higher Media Multi-Tasking Activity Is Associated with Smaller Gray-Matter Density in the Anterior Cingulate Cortex (2014)
  42. Altered brain activation during response inhibition and error processing in subjects with Internet gaming disorder: a functional magnetic imaging study (2014)
  43. The prefrontal dysfunction in individuals with Internet gaming disorder: a meta-analysis of functional magnetic resonance imaging studies (2014)
  44. Trait impulsivity and impaired prefrontal impulse inhibition function in adolescents with internet gaming addiction revealed by a Go/No-Go fMRI study (2014)
  45. PET imaging reveals brain functional changes in internet gaming disorder (2014)
  46. Brain correlates of response inhibition in Internet gaming disorder (2014)
  47. Proton magnetic resonance spectroscopy (MRS) in on-line game addiction (2014)
  48. Physiological arousal deficits in addicted gamers differ based on preferred game genre (2014)
  49. Neurophysiological and neuroimaging aspects between internet gaming disorder and alcohol use disorder (2014)
  50. Virtual reality therapy for internet gaming disorder (2014)
  51. Abnormal gray matter and white matter volume in 'Internet gaming addicts' (2014)
  52. Altered cingulate-hippocampal synchrony correlate with aggression in adolescents with internet gaming disorder (2014)
  53. Impaired risk evaluation in people with Internet gaming disorder: fMRI evidence from a probability discounting task (2014)
  54. Reduced fiber integrity and cognitive control in adolescents with internet gaming disorder (2014)
  55. Assessment of in vivo microstructure alterations in gray matter using DKI in internet gaming addiction (2014)
  56. EEG and ERP based Degree of Internet Game Addiction Analysis (2014)
  57. Decreased functional connectivity in an executive control network is related to impaired executive function in Internet gaming disorder (2014)
  58. Different resting-state functional connectivity alterations in smokers and nonsmokers with internet gaming addiction (2014)
  59. A selective involvement of putamen functional connectivity in youth with internet gaming disorder (2014)
  60. Similarities and differences among Internet gaming disorder, gambling disorder and alcohol use disorder: A focus on impulsivity and compulsivity (2014)
  61. Blunted feedback processing during risk-taking in adolescents with features of problematic Internet use (2015)
  62. Brain structures and functional connectivity associated with individual differences in Internet tendency in healthy young adults (2015)
  63. Examination of neural systems sub-serving facebook "addiction" (2014)
  64. A Short Summary of Neuroscientific Findings on Internet Addiction (2015) PDF
  65. New developments on the neurobiological and pharmaco-genetic mechanisms underlying internet and videogame addiction (2015)
  66. Electroencephalogram Feature Detection and Classification in People with Internet Addiction Disorder with Visual Oddball Paradigm (2015)
  67. Molecular and Functional Imaging of Internet Addiction (2015)
  68. Aberrant corticostriatal functional circuits in adolescents with Internet addiction disorder (2015).
  69. How Has the Internet Reshaped Human Cognition? (2015)
  70. Problematic Internet Usage and Immune Function (2015)
  71. Neural substrates of risky decision making in individuals with Internet addiction (2015)
  72. Relationship between peripheral blood dopamine level and internet addiction disorder in adolescents: a pilot study (2015)
  73. Problematic internet use is associated with structural alterations in the brain reward system in females. (2015)
  74. Working memory, executive function and impulsivity in Internet-addictive disorders: a comparison with pathological gambling (2015)
  75. Disrupted inter-hemispheric functional and structural coupling in Internet addiction adolescents (2015)
  76. Electrophysiological studies in internet addiction: A review within the dual-process framework (2015)
  77. Biological basis of problematic internet use (PIN) and therapeutic implications (2015)
  78. Differences in functional connectivity between alcohol dependence and internet gaming disorder (2015)
  79. Core brain networks interactions and cognitive control in internet gaming disorder individuals in late adolescence/early adulthood (2015)
  80. Altered gray matter density and disrupted functional connectivity of the amygdala in adults with Internet gaming disorder (2015)
  81. Resting-state regional homogeneity as a biological marker for patients with Internet gaming disorder: A comparison with patients with alcohol use disorder and healthy controls (2015)
  82. Altered reward processing in pathological computer gamers: ERP-results from a semi-natural Gaming-Design (2015)
  83. Striatum morphometry is associated with cognitive control deficits and symptom severity in internet gaming disorder (2015)
  84. Video game training and the reward system (2015)
  85. Decreased Prefrontal Lobe Interhemispheric Functional Connectivity in Adolescents with Internet Gaming Disorder: A Primary Study Using Resting-State fMRI (2015)
  86. Functional characteristics of the brain in college students with internet gaming disorder (2015)
  87. The alteration of gray matter volume and cognitive control in adolescents with internet gaming disorder (2015)
  88. An fMRI study of cognitive control in problem gamers (2015)
  89. Altered resting-state functional connectivity of the insula in young adults with Internet gaming disorder (2015)
  90. Imbalanced functional link between executive control network and reward network explain the online-game seeking behaviors in Internet gaming disorder (2015)
  91. Is the Internet gaming-addicted brain close to be in a pathological state? (2015)
  92. Altered Cardiorespiratory Coupling in Young Male Adults with Excessive Online Gaming (2015)
  93. Altered Brain Reactivity to Game Cues After Gaming Experience (2015)
  94. The Effects of Video Games on Cognition and Brain Structure: Potential Implications for Neuropsychiatric Disorders (2015)
  95. Dysfunction of the frontolimbic region during swear word processing in young adolescents with Internet gaming disorder (2015)
  96. Abnormal prefrontal cortex resting state functional connectivity and severity of internet gaming disorder (2015)
  97. Neurophysiological features of Internet gaming disorder and alcohol use disorder: a resting-state EEG study (2015)
  98. Game addiction (2015)
  99. Decreased functional connectivity between ventral tegmental area and nucleus accumbens in Internet gaming disorder: evidence from resting state functional magnetic resonance imaging (2015)
  100. Compromised Prefrontal Cognitive Control Over Emotional Interference in Adolescents with Internet Gaming Disorder (2015)
  101. Frequency-dependent changes in the amplitude of low-frequency fluctuations in internet gaming disorder (2015)
  102. The inhibition of proactive interference among adults with Internet gaming disorder (2015)
  103. Decreased modulation by the risk level on the brain activation during decision making in adolescents with internet gaming disorder (2015)
  104. Neurobiological correlates of internet gaming disorder: Similarities to pathological gambling (2015)
  105. Brain connectivity and psychiatric comorbidity in adolescents with Internet gaming disorder (2015)
  106. Testing the Predictive Validity and Construct of Pathological Video Game Use (2015)
  107. Impaired inhibition and working memory in response to internet-related words among adolescents with internet addiction: A comparison with attention-deficit/hyperactivity disorder (2016)
  108. Deficit in rewarding mechanisms and prefrontal left/right cortical effect in vulnerability for internet addiction (2016)
  109. Functional magnetic resonance imaging of internet addiction in young adults (2016)
  110. Problematic Internet Users Show Impaired Inhibitory Control and Risk Taking with Losses: Evidence from Stop Signal and Mixed Gambles Tasks (2016)
  111. Altered Gray Matter Volume and White Matter Integrity in College Students with Mobile Phone Dependence (2016)
  112. Cue-induced craving for Internet among Internet addicts (2016)
  113. Functional changes in patients with internet addiction disclosed by adenosine stressed cerebral blood flow perfusion imaging 99mTc-ECD SPET (2016)
  114. Respiratory sinus arrhythmia reactivity of internet addiction abusers in negative and positive emotional states using film clips stimulation (2016)
  115. Neurobiological findings related to Internet use disorders (2016)
  116. Texting Dependence, iPod Dependence, and Delay Discounting (2016)
  117. Physiological markers of biased decision-making in problematic Internet users (2016)
  118. The dysfunction of face processing in patients with internet addiction disorders: an event-related potential study (2016)
  119. Internet use: Molecular influences of a functional variant on the OXTR gene, the motivation behind using the Internet, and cross-cultural specifics (2016)
  120. A Two-Stage Channel Selection Model for Classifying EEG Activities of Young Adults with Internet Addiction (2016)
  121. An Affective Neuroscience Framework for the Molecular Study of Internet Addiction (2016)
  122. Brain oscillations, inhibitory control mechanisms and rewarding bias in internet addiction (2016)
  123. Impact of videogame play on the brain’s microstructural properties: cross-sectional and longitudinal analyses (2016)
  124. Activation of the ventral and dorsal striatum during cue reactivity in Internet gaming disorder (2016)
  125. Brain connectivity and psychiatric comorbidity in adolescents with Internet gaming disorder (2016)
  126. Frontostriatal circuits, resting state functional connectivity and cognitive control in internet gaming disorder (2016)
  127. Dysfunctional information processing during an auditory event-related potential task in individuals with Internet gaming disorder (2016)
  128. Resting-State Peripheral Catecholamine and Anxiety Levels in Korean Male Adolescents with Internet Game Addiction (2016)
  129. Network-Based Analysis Reveals Functional Connectivity Related to Internet Addiction Tendency (2016)
  130. Altered Functional Connectivity of the Insula and Nucleus Accumbens in Internet Gaming Disorder: A Resting State fMRI Study (2016)
  131. Violence-related content in video game may lead to functional connectivity changes in brain networks as revealed by fMRI-ICA in young men (2016)
  132. Attentional bias in excessive Internet gamers: Experimental investigations using an addiction Stroop and a visual probe (2016)
  133. Decreased functional connectivity of insula-based network in young adults with internet gaming disorder (2016)
  134. Dysfunctional default mode network and executive control network in people with Internet gaming disorder: Independent component analysis under a probability discounting task (2016)
  135. Impaired anterior insular activation during risky decision making in young adults with internet gaming disorder (2016)
  136. Altered Structural Correlates of Impulsivity in Adolescents with Internet Gaming Disorder (2016)
  137. Dysfunctional information processing during an auditory event-related potential task in individuals with Internet gaming disorder (2016)
  138. Functional characteristics of the brain in college students with internet gaming disorder (2016)
  139. Brain Activity toward Gaming-Related Cues in Internet Gaming Disorder during an Addiction Stroop Task (2016)
  140. Cue-induced Behavioral and Neural Changes among Excessive Internet Gamers and Possible Application of Cue Exposure Therapy to Internet Gaming Disorder (2016)
  141. Neurochemical correlates of internet game play in adolescents with attention deficit hyperactivity disorder: A proton magnetic resonance spectroscopy (MRS) study (2016)
  142. Altered resting-state neural activity and changes following a craving behavioral intervention for Internet gaming disorder (2016)
  143. Exploring the Neural Basis of Avatar Identification in Pathological Internet Gamers and of Self-Reflection in Pathological Social Network Users (2016)
  144. Altered brain functional networks in people with Internet gaming disorder: Evidence from resting-state fMRI (2016)
  145. A comparative study of the effects of bupropion and escitalopram on Internet gaming disorder (2016)
  146. Impaired executive control and reward circuit in Internet gaming addicts under a delay discounting task: independent component analysis (2016)
  147. Effects of craving behavioral intervention on neural substrates of cue-induced craving in Internet gaming disorder (2016)
  148. The topological organization of white matter network in internet gaming disorder individuals (2016)
  149. Altered Autonomic Functions and Distressed Personality Traits in Male Adolescents with Internet Gaming Addiction (2016)
  150. Effects of outcome on the covariance between risk level and brain activity in adolescents with internet gaming disorder (2016)
  151. Changes of quality of life and cognitive function in individuals with Internet gaming disorder: A 6-month follow-up (2016)
  152. Compensatory increase of functional connectivity density in adolescents with internet gaming disorder (2016)
  153. Heart rate variability of internet gaming disorder addicts in emotional states (2016)
  154. Delay discounting, risk-taking, and rejection sensitivity among individuals with Internet and Video Gaming Disorders (2016)
  155. Electrophysiological studies in Internet addiction: A review within the dual-process framework (2017)
  156. Altered default mode, fronto-parietal and salience networks in adolescents with Internet addiction (2017)
  157. The role of emotional inhibitory control in specific internet addiction - an fMRI study (2017)
  158. Neural correlate of Internet use in patients undergoing psychological treatment for Internet addiction (2017)
  159. Brain anatomy alterations associated with Social Networking Site addiction (2017)
  160. Effect of electro-acupuncture combined with psychological intervention on mental symptoms and P50 of auditory evoked potential in patients with internet addiction disorder (2017)
  161. Time Is Money: The Decision Making of Smartphone High Users in Gain and Loss Intertemporal Choice (2017)
  162. The cognitive dysregulation of Internet addiction and its neurobiological correlates (2017)
  163. Facebook usage on smartphones and gray matter volume of the nucleus accumbens (2017)
  164. Deficits in recognizing disgust facial expressions and Internet addiction: Perceived stress as a mediator (2017)
  165. Spontaneous Hedonic Reactions to Social Media Cues (2017)
  166. Differential physiological changes following internet exposure in higher and lower problematic internet users (2017)
  167. Differences in Resting-state Quantitative Electroencephalography Patterns in Attention Deficit/Hyperactivity Disorder with or without Comorbid Symptoms (2017)
  168. Abnormal Reward and Punishment Sensitivity Associated with Internet Addicts (2017)
  169. Evidences from Rewarding System, FRN and P300 Effect in Internet-Addiction in Young People (2017)
  170. Web addiction in the brain: Cortical oscillations, autonomic activity, and behavioral measures (2017)
  171. Extracting the Values of Resting-state Functional Connectivity that Correlate with a Tendency of Internet Addiction (2017)
  172. Association between physiological oscillations in self-esteem, narcissism and internet addiction: A cross-sectional study (2017)
  173. The impact of Internet Dependence on College Student's attention networks (2017)
  174. Electro-acupuncture treatment for internet addiction: Evidence of normalization of impulse control disorder in adolescents (2017)
  175. Cue-induced craving in Internet-communication disorder using visual and auditory cues in a cue-reactivity paradigm (2017)
  176. Delay Discounting of Video Game Players: Comparison of Time Duration Among Gamers (2017)
  177. Stress vulnerability in male youth with Internet Gaming Disorder (2017)
  178. Neurophysiological correlates of altered response inhibition in internet gaming disorder and obsessive-compulsive disorder: Perspectives from impulsivity and compulsivity (2017)
  179. Gaming increases craving to gaming-related stimuli in individuals with Internet gaming disorder (2017)
  180. Altered functional connectivity in default mode network in Internet gaming disorder: Influence of childhood ADHD (2017)
  181. Individual differences in implicit learning abilities and impulsive behavior in the context of Internet addiction and Internet Gaming Disorder under the consideration of gender (2017)
  182. New developments in brain research of internet and gaming disorder (2017)
  183. Associations between prospective symptom changes and slow-wave activity in patients with Internet gaming disorder: A resting-state EEG study (2017)
  184. Response Inhibition and Internet Gaming Disorder: A Meta-analysis (2017)
  185. Dissociable neural processes during risky decision-making in individuals with Internet-gaming disorder (2017)
  186. The correlation between mood states and functional connectivity within the default mode network can differentiate Internet gaming disorder from healthy controls (2017)
  187. Neural connectivity in Internet gaming disorder and alcohol use disorder: A resting-state EEG coherence study (2017)
  188. Structural alterations in the prefrontal cortex mediate the relationship between Internet gaming disorder and depressed mood (2017)
  189. Exploratory metabolomics of biomarker identification for the internet gaming disorder in young Korean males (2017)
  190. Cognitive control and reward loss processing in Internet gaming disorder: Results from a comparison with recreational Internet game-users (2017)
  191. Comparison of Electroencephalography (EEG) Coherence between Major Depressive Disorder (MDD) without Comorbidity and MDD Comorbid with Internet Gaming Disorder (2017)
  192. The adaptive decision-making, risky decision, and decision-making style of Internet gaming disorder (2017)
  193. Unconscious Processing of Facial Expressions in Individuals with Internet Gaming Disorder (2017).
  194. Altered hippocampal volume and functional connectivity in males with Internet gaming disorder comparing to those with alcohol use disorder (2017)
  195. Altered coupling of default-mode, executive-control and salience networks in Internet gaming disorder (2017)
  196. Difference in the functional connectivity of the dorsolateral prefrontal cortex between smokers with nicotine dependence and individuals with internet gaming disorder (2017)
  197. Altered Brain Activities Associated with Craving and Cue Reactivity in People with Internet Gaming Disorder: Evidence from the Comparison with Recreational Internet Game Users (2017)
  198. Impact of video games on plasticity of the hippocampus (2017)
  199. Differential neurophysiological correlates of information processing in Internet gaming disorder and alcohol use disorder measured by event-related potentials (2017)
  200. Video Game Addiction in Emerging Adulthood: Cross-Sectional Evidence of Pathology in Video Game Addicts as Compared to Matched Healthy Controls (2017)
  201. Diffusion tensor imaging of the structural integrity of white matter correlates with impulsivity in adolescents with internet gaming disorder (2017)
  202. An Overview of Structural Characteristics in Problematic Video Game Playing (2017)
  203. Group independent component analysis reveals alternation of right executive control network in Internet gaming disorder (2017)
  204. Sustained dysfunctional information processing in patients with Internet gaming disorder: 6-month follow-up ERP study (2017)
  205. Abnormal gray matter volume and impulsivity in young adults with Internet gaming disorder (2017)
  206. An Update Overview on Brain Imaging Studies of Internet Gaming Disorder (2017)
  207. Comparison of brain connectivity between Internet gambling disorder and Internet gaming disorder: A preliminary study (2017)
  208. Impulsivity and compulsivity in Internet gaming disorder: A comparison with obsessive-compulsive disorder and alcohol use disorder (2017)
  209. Impaired Feedback Processing for Symbolic Reward in Individuals with Internet Game Overuse (2017)
  210. Orbitofrontal gray matter deficits as marker of Internet gaming disorder: converging evidence from a cross-sectional and prospective longitudinal design (2017)
  211. Comparing the Effects of Bupropion and Escitalopram on Excessive Internet Game Play in Patients with Major Depressive Disorder (2017)
  212. Impaired Empathy Processing in Individuals with Internet Addiction Disorder: An Event-Related Potential Study (2017)
  213. Structural Brain Network Abnormalities In Subjects With Internet Addiction (2017)
  214. Relationship between Internet Addiction with Physical Fitness, Hemoglobin Levels and Leukocyte Levels to Students (2017)
  215. An Analysis of Smartphone Overuse Recognition in Terms of Emotions using Brainwaves and Deep Learning (2017)
  216. Functional and structural neural alterations in Internet gaming disorder: A systematic review and meta-analysis (2017)
  217. Is Neural Processing of Negative Stimuli Altered in Addiction Independent of Drug Effects? Findings from Drug-Naïve Youth with Internet Gaming Disorder (2017)
  218. Internet Addiction Creates Imbalance in the Brain (2017)
  219. Acute effects of video-game playing versus television viewing on stress markers and food intake in overweight and obese young men: A randomised controlled trial (2018)

 

Slide 20 also stated that internet addiction studies had documented the reversal of symptoms and addiction-related brain changes. Thirty such studies were provided in the updated support section of Slide 11.


SLIDE 21

At last, we have groups of guys who are no longer using Internet porn. That’s right. Heavy users are voluntarily giving it up by the thousands. These guys are the missing “control group” in the great porn experiment. They’re showing the experts what changing one variable can do.

ORIGINAL SUPPORT:

Just a few of the hundreds of forums we have seen discussing healing porn-related problems by eliminating a single variable: porn.

About 5,000 documented stories where men (and a few women) eliminated porn use and healed severe symptoms, including chronic sexual dysfunctions, mental and emotional problems:

Hundreds of more self-reports by young porn users who reported various symptoms and conditions abating after eliminating porn:

UPDATED SUPPORT:

The best way to assess porn's effects is to have users take a break. In 2011 such studies had yet to be published. So I relied on anecdotes. However, in 2016 I published this peer-reviewed paper in the journal Addicta: Eliminate Chronic Internet Pornography Use to Reveal Its Effect (2016).  In the paper I describe a handful of studies that had porn users eliminate a single variable – internet porn. As of 2017, there are only 8 studies where porn users attempted to abstain from porn. All 8 studies reported significant results. Five of the eight studies had compulsive porn users with severe sexual dysfunctions abstain from porn. Those 5 studies demonstrate causation as patients healed chronic sexual dysfunctions by removing a single variable (pornography):

  1. Male masturbation habits and sexual dysfunctions (2016)
  2. Is Internet Pornography Causing Sexual Dysfunctions? A Review with Clinical Reports (2016)
  3. Unusual masturbatory practice as an etiological factor in the diagnosis and treatment of sexual dysfunction in young men (2014)
  4. Situational Psychogenic Anejaculation: A Case Study (2014)
  5. How difficult is it to treat delayed ejaculation within a short-term psychosexual model? A case study comparison (2017)

The other three studies:

6) Trading Later Rewards for Current Pleasure: Pornography Consumption and Delay Discounting (2015) - The more pornography that participants consumed, the less able they were to delay gratification. This unique study also had porn users reduce porn use for 3 weeks. The study found that continued porn use was causally related to greater inability to delay gratification (note that the ability to delay gratification is a function of the prefrontal cortex). The first study (median subject age 20) correlated subjects' pornography use with their scores on a delayed gratification task. Excerpt:

The more pornography that participants consumed, the more they saw the future rewards as worth less than the immediate rewards, even though the future rewards were objectively worth more.

A second study (median age 19) was performed to assess if porn use causes delayed discounting, or the inability to delay gratification. Researchers divided current porn users into two groups:

  1. One group abstained from porn use for 3 weeks,
  2. A second group abstained from their favorite food for 3 weeks.

All participants were told the study was about self-control, and they were randomly chosen to abstain from their assigned activity. The clever part was that the researchers had the second group of porn users abstain from eating their favorite food. This ensured that 1) all subjects engaged in a self-control task, and 2) the second group's porn use was unaffected. At the end of the 3 weeks, participants were involved in a task to assess delay discounting. Important note: While the "porn abstinence group" viewed significantly less porn than the "favorite food abstainers," most did not completely abstain from porn viewing. The results:

As predicted, participants who exerted self-control over their desire to consume pornography chose a higher percentage of larger, later rewards compared to participants who exerted self-control over their food consumption but continued consuming pornography.

The group that cut back on their porn viewing for 3 weeks displayed less delay discounting than the group that simply abstained from their favorite food. Put simply, abstaining from internet porn increases porn users' ability to delay gratification. From the study:

Thus, building on the longitudinal findings of Study 1, we demonstrated that continued pornography consumption was causally related to a higher rate of delay discounting. Exercising self-control in the sexual domain had a stronger effect on delay discounting than exercising self-control over another rewarding physical appetite (e.g., eating one’s favorite food).

7) How Abstinence Affects Preferences (2016) [preliminary results] – Excerpts from the article:

Results of the First Wave - Main Findings

  1. The length of the longest streak participants performed before taking part in the survey correlates with time preferences. The second survey will answer the question if longer periods of abstinence render participants more able to delay rewards, or if more patient participants are more likely to perform longer streaks.
  2. Longer periods of abstinence most likely cause less risk aversion (which is good). The second survey will provide the final proof.
  3. Personality correlates with length of streaks. The second wave will reveal if abstinence influences personality or if personality can explain variation in the length of streaks.

Results of the Second Wave - Main Findings

  1. Abstaining from pornography and masturbation increases the ability to delay rewards
  2. Participating in a period of abstinence renders people more willing to take risks
  3. Abstinence renders people more altruistic
  4. Abstinence renders people more extroverted, more conscientious, and less neurotic

8) A Love That Doesn’t Last: Pornography Consumption and Weakened Commitment to One’s Romantic Partner (2012) – The study had subjects try to abstain from porn use for 3 weeks. Upon comparing the two groups, those who continued using pornography reported lower levels of commitment than those who tried to abstain. Excerpts:

The intervention proved effective at reducing or eliminating pornography consumption for the duration of the three-week study, yet did not deter control participants from continuing their consumption. Our hypothesis was supported as participants in the pornography consumption condition reported a substantial reduction in commitment compared to participants in the abstain from pornography condition.

Also, the effect of continued pornography consumption on commitment cannot be explained by a difference in the depletion of self-regulatory resources from exercising greater self-control, as participants in both conditions abstained from something pleasurable (i.e., pornography or a favorite food).

Studies linking porn use to the symptoms described in The Great Porn Experiment:


SLIDE 22

It’s the “resurrection of guys.” Before I continue, you probably want to know why any porn-loving guy in his right mind would give it up. Two words:

ORIGINAL SUPPORT:

See preceding slide.


SLIDE 23

Erectile dysfunction. “Internet porn is killing young men’s sexual performance.” As Zimbardo said, “Young guys are flaming out with women.” This survey by Italian urologists confirms what we have witnessed over the last few years.

ORIGINAL SUPPORT:

Philip Zimbardo's "Demise of Guys" TED talk, where he said, “Young guys are flaming out with women.”

Dr. Carlo Foresta is a urology professor, president of the Italian Society of Reproductive Pathophysiology, and author of some 300 academic studies. Articles where Dr. Foresta stated that “Internet porn is killing young men’s sexual performance.”

About 5,000 documented stories where men (and a few women) eliminated porn use and healed chronic sexual dysfunctions.

Porn recovery forums - sections devoted to porn-induced sexual dysfunctions:

An extensive New York Magazine article about an emerging phenomenon: porn-induced sexual problems:

UPDATED SUPPORT:

Dr. Philip Zimbardo: In support of his TED talk Dr. Zimbardo published two books (each describes porn-induced sexual dysfunctions):

Dr. Carlo Foresta followed up his 2011 press release with:

  • A 2014 lecture describing upcoming studies - The lecture contains the results of longitudinal and cross-sectional studies. One study involved a survey of high school teens (pages 52-53). The study reported that sexual dysfunction doubled between 2005 and 2013, with low sexual desire increasing 600%. The percentage of teens that experienced alterations of their sexuality: 2004/05: 7.2%, 2012/13: 14.5% The percentage of teens with low sexual desire: 2004/05: 1.7%, 2012/13: 10.3% (that's a 600% increase in 8 years). Dr. Foresta also describes his upcoming study, "Sexuality media and new forms of sexual pathology sample 125 young males, 19-25 years" (Italian name - "Sessualità mediatica e nuove forme di patologia sessuale Campione 125 giovani maschi"). The results from the study (pages 77-78), which used the International Index of Erectile Function Questionnaire, found that regular porn users scored 50% lower on sexual desire domain and 30% lower of the erectile functioning domain.
  • Peer-reviewed study: Adolescents and web porn: a new era of sexuality (2015) - This Italian study analyzed the effects of Internet porn on high school seniors, co-authored by Carlo Foresta, president of the Italian Society of Reproductive Pathophysiology. The most interesting finding is that 16% of those who consume porn more than once a week report abnormally low sexual desire compared with 0% in non-consumers (and 6% for those who consume less than once a week).

Since 2011 over 100 sexual experts (urology professors, urologists, psychiatrists, psychologists, sexologists, MDs) who acknowledge and treat porn-induced sexual problems have published articles or appeared on radio and TV. Note: Urologists have twice presented evidence of porn-induced sexual dysfunctions at annual conferences of the American Urological Association.

  1. Video of a lecture: Porn-induced ED (parts 1-4) presented at the American Urologic Association Conference, May 6-10, 2016. Urologist Tarek Pacha.
  2. New findings: Study sees link between porn and sexual dysfunction (2017) - Data from an upcoming study, presented at the 2017 American Urological Association Conference.

List of articles, broadcasts, radio shows, and podcasts that involve sexual experts who confirm the existence of porn-induced sexual dysfunctions:

  1. Too Much Internet Porn May Cause Impotence, urology professor Carlo Foresta (2011)
  2. The Young Turks discuss porn-induced ED (2011)
  3. Porning too much? by Robert Taibbi, L.C.S.W. (2012)
  4. Does Porn Contribute to ED? by Tyger Latham, Psy.D. in Therapy Matters (2012)
  5. Urologist Lim Huat Chye:  Pornography can cause erectile dysfunction for young men (2012)
  6. Director of Middlebury College Health Center, Dr. Mark Peluso, sees rise in ED: blames porn (2012)
  7. Sexual Dysfunction: The Escalating Price of Abusing Porn (2012)
  8. "Addicted to Viagra: They should be at their most virile, but a growing number of young men can’t cope without those little blue pills" (2012)
  9. Hardcore corruption of the human hard disk (2012)
  10. The Dr. Oz Show addresses Porn-induced ED (2013)
  11. Erectile dysfunction increases among young men, sex therapist Brandy Engler, PhD (2013)
  12. Internet Porn and Erectile Dysfunction, by Urologist James Elist, F.A.C.S., F.I.C.S. (2013)
  13. How porn is destroying modern sex lives: Feminist writer Naomi Wolf has an unsettling explanation for why Britons are having less sex (2013)
  14. Pornography & Erectile Dysfunction, by Lawrence A. Smiley M.D. (2013)
  15. Urologist Andrew Kramer discusses ED - including porn-induced ED (2013)
  16. Is Porn Destroying Your Sex Life? By Robert Weiss LCSW, CSAT-S (2013)
  17. Too Much Internet Porn: The SADD Effect, by Ian Kerner PhD. (2013)
  18. Solutions for porn-induced erectile dysfunction, by Sudeepta Varma, MD, Psychiatry (2013)
  19. Dr. Rosalyn Dischiavo on porn-induced ED (2013)
  20. Did porn warp me forever? Salon.com (2013)
  21. Radio Show: Young Psychiatrist Discusses His Porn-induced ED (2013)
  22. Video by Medical Doctor: Causes of ED in young men - includes Internet porn (2013)
  23. Chris Kraft, Ph.D. - Johns Hopkins sexologist discusses porn-induced sexual dysfunctions (2013)
  24. Why A Sex Therapist Worries About Teens Viewing Internet Porn, by Dr. Aline Zoldbrod (2013)
  25. Is “Normal” Porn Watching Affecting Your Manhood? by sexologist Maryline Décarie, M.A. (2013)
  26. 'Porn' makes men hopeless in bed: Dr Deepak Jumani, Sexologist Dhananjay Gambhire (2013)
  27. Need porn diet for three to five months to get an erection again, Alexandra Katehakis MFT, CSAT-S (2013)
  28. Just Can't Get It Up: ZDoggMD.com (2013)
  29. Time-out cures man of Internet porn addiction & ED: CBS video, Dr. Elaine Brady (2013)
  30. Seven Sharp with Caroline Cranshaw - The damage caused by internet porn addiction (2013)
  31. Reality is not enough exciting (Swedish), psychiatrist Goran Sedvallson. urologist Stefan Arver, psychotherapist Inger Björklund (2013)
  32. Why porn and masturbation can be too much of a good thing, Dr. Elizabeth Waterman (2013)
  33. Dan Savage answers question about porn-induced ED (12-2013)        
  34. Irish Times: 'I can’t get stimulated unless I watch porn with my girlfriend' (2016)
  35. Erection problems from too much porn - Swedish (2013)
  36. Internet porn wrecking conjugal ties in India (Porn-induced ED), Dr. Narayana Reddy (2013)
  37. Pornography was the only one who got Donald aroused: Swedish (2013)
  38. Men who watch too much porn can't get it up, warns Manchester sex therapist (2014)
  39. What causes erectile dysfunction?, Dr. Lohit K, M.D (2014)
  40. Has Porn Ruined Our Sex Lives Forever? The Daily Dose. (2014)
  41. Suffering from ED? This Reason May Surprise You, by Michael S Kaplan, MD (2014)
  42. Is porn addiction on the rise in Bangalore? (2014)
  43. YBOP review of "The New Naked" by urologist Harry Fisch, MD (2014)
  44. Behind the documentary: Porn-Induced Erectile Dysfunction, Global News Canada (2014)
  45. 'Generation X-Rated' (Porn-Induced ED) - Urologist Abraham Morgentaler (2014)
  46. Porn-induced erectile dysfunction in healthy young men, Andrew Doan MD, PhD (2014)
  47. Catastrophic effects of adolescent porn addiction. Wrishi Raphael, MD (2014)
  48. Porn causing erectile dysfunction in young men, by Global News Canada (2014)                                                                                                                 
  49. LIVE BLOG: Porn-induced erectile dysfunction. Dr. Abraham Morgentaler, Gabe Deem (2014)
  50. Watching porn can cause male sexual dysfunction. Urologists David B. Samadi & Muhammed Mirza (2014)
  51. Looking at porn on the internet could ruin your sex life, doctor says. Harry Fisch, MD (2014)
  52. Online Videos Causing IRL Erectile Problems? by Andrew Smiler PhD (2014)
  53. Do You Masturbate Too Much? Urologist Tobias Köhler, Therapist Dan Drake (2014)
  54. How Online Sexual Stimulation Can Lead to In Real Life Sexual Dysfunction, by Jed Diamond PhD (2014)
  55. Too Much Porn Contributing to ED: Urologist Fawad Zafar (2014)
  56. Is Porn Erectile Dysfunction Fact or Fiction? by Kurt Smith, LMFT, LPCC, AFC (2015)
  57. When porn becomes a problem (Irish Times). Sex therapists Trish Murphy, Teresa Bergin, Tony Duffy (2015)
  58. Porn Addiction, Porn Creep and Erectile Dysfunction By Billi Caine, B.Sc Psych, RN (2015)
  59. Online pornography and compulsive masturbation cause impotence in young, Emilio Loiacono MD (2015)
  60. Counsellors battle ‘plague of pornography’, psychologists Seema Hingorrany & Yolande Pereira, paediatrician, Samir Dalwai (2015)
  61. Tinder and the Dawn of the “Dating Apocalypse”, Vanity Fair (2015)
  62. TEDX talk about porn-induced ED & reclaiming one's sexuality: "How to Become a Sex God" by Gregor Schmidinger (2015)
  63. Torn on porn: A look at addiction & pornography. Dr. Charlotte Loppie, University of Victoria Professor in the School of Public Health (2016)
  64. Nurse wants residents to talk about erectile dysfunction. Lesley Mills, a consultant nurse in sexual dysfunction (2016)
  65. How internet porn is creating a generation of men desensitised to real life sex. Dr Andrew Smiler, Dr Angela Gregory (2016)
  66. BBC: Easy access to online porn is 'damaging' men's health, says NHS therapist. Psychosexual therapist Angela Gregory (2016)
  67. What to Do When You’re Dating a Guy with Problems Below the Belt. Sexologist Emily Morse, Ph.D. (2016)
  68. Non-prescription Viagra has infiltrated the bedrooms of today’s young black men. Urology professor David B. Samadi & Muhammed Mirza, MD founder of ErectileDoctor.com (2016)
  69. The Devastating Consequences of Pornography. Dr. Ursula Ofman (2016)
  70. "Porn addiction could ruin your sex life and here's why". Sexual function specialist Anand Patel MD, Sex therapist Janet Eccles, Neuroscientist Dr Nicola Ray (2016)
  71. Podcast: Porn-induced erectile dysfunction (PIED). By world renowned urologist Dudley Danoff & Dr. Diana Wiley (2016)
  72. The REAL reason young men suffer from erectile dysfunction, by Anand Patel, MD (2016)
  73. Turn away! Why pornography can harm your sex life. By urology professor Dr. David Samadi (2016)
  74. Urology Times asks: "What is driving younger men to seek treatment for ED?" Jason Hedges, MD, PhD (2016)
  75. Why Men are quitting Internet Porn (porn-induced ED), Andrew Doan, MD, PhD (2016)
  76. How the proliferation of porn is ruining men's love lives. By Angela Gregory Lead for Psychosexual Therapy, Chandos Clinic, Nottingham U. Secretary British Society of Sexual Medicine (2016)
  77. A lot of cases relating to erectile dysfunction relate to pornography addiction and use. Zoe Hargreaves, NHS Psychosexual Therapist (2016)
  78. The insidious impact of internet porn. by Rose Laing MD (2016)
  79. Salvaging sex life from erectile dysfunction, Dalal Akoury MD (2016)
  80. Non-prescription Viagra has infiltrated the bedrooms of today’s young black men. Urology professor David B. Samadi & Muhammed Mirza, MD founder of ErectileDoctor.com (2016)
  81. Too much porn can lead to ED, Malaysian men warned. Clinical andrologist Dr Mohd Ismail Mohd Tambi (2016)
  82. The black and white of blue films: How porn addiction damages relationships. by Sandip Deshpande, MD (2016)
  83. Private school principals get a lesson in porn. Sexuality educator Liz Walker (2016)
  84. Six Signs that your Partner has a Pornography Addiction & What you can Do. by Diana Baldwin LCSW (2016)
  85. Is Porn Good For Us or Bad For Us? by Philip Zimbardo PhD. (2016)
  86. How Porn is Hijacking the Sex Lives of Our Young Men. by Dr. Barbara Winter (2016)
  87. A shocking new TV show aired last night and it sees young people encouraged to air their sexual problems and woes. Dr. Vena Ramphal (2016)
  88. How To Solve Common Sexual Issues, Because They May Be Mental, Physical, Or Both. Eyal Matsliah author of "Orgasm Unleashed" (2016)
  89. South African therapists and sex educators say interventions are needed to stop today’s youngsters suffering serious health effects later in life due to pornography addiction (2016)
  90. Cybersex Addiction: A Case Study. Dorothy Hayden, LCSW (2016)
  91. How Porn Wrecks Relationships, Barbara Winter, Ph.D. (2016)
  92. Porn Can Help A Relationship, But Proceed With Caution. Amanda Pasciucco LMFT, CST; Wendy Haggerty LMFT, CST (2016)
  93. How Internet Porn Is Making Young Men Impotent. Sex therapist and associate of Impotence Australia, Alinda Small (2016)
  94. Video - Guyology founder Melisa Holmes MD talks about how boys develop porn-induced erectile dysfunction with many needing Viagra (2017)
  95. Video: Hormone expert Dr. Kathryn Retzler discusses porn-induced erectile dysfunction (2017)
  96. Video: Porn-Induced Erectile Dysfunction by Brad Salzman, LCSW, CSAT (2017)
  97. Irish children as young as seven are being exposed to porn. Dr Fergal Rooney (2017)
  98. Here's how porn is affecting Irish relationships. Sex therapist Teresa Bergin (2017)
  99. Is Technology Ruining Our Brains? (Comedy Central show). Alexandra Katehakis, MFT, CSAT-S, CST-S (2017)
  100. How to educate our youth about pornography addiction and dangers. Psychosexual therapists Nuala Deering & Dr. June Clyne (2017)
  101. Video - Can Porn Induce Erectile Dysfunction and Impotence? by Paul Kattupalli MD (2016)
  102. 'Porn is a public health crisis': experts call for government inquiry into health effects of porn. Sex therapist Mary Hodson (2017)
  103. Everything You Need To Know About Porn-Induced Erectile Dysfunction. Dr. Ralph Esposito; Elsa Orlandini Psy.D. (2017)
  104. Don’t let erectile dysfunction get you down. Psychotherapist Nuala Deering (2017)
  105. How watching porn can cause erectile dysfunction. Dr Lubda Nadvi (2017)
  106. This Is How Therapists Treat Young Men With "Porn-Induced Erectile Dysfunction". Sex therapist Alinda Small, clinical sexologist Tanya Koens, psychotherapist Dan Auerbach (2017)
  107. TEDx Talk "Sex, Porn & Manhood" (Professor Warren Binford, 2017)
  108. Online Porn: Fastest growing addiction in the U.S. Sex addiction therapist, Chris Simon (2017)
  109. Can Watching Too Much Porn Affect Your Sex Life? Jenner Bishop, LMFT; Psychotherapist Shirani M. Pathak (2017)
  110. Young people report 'persistent and distressing' problems with sex lives: study (2017)
  111. 'Tidal wave' of porn addiction as experts warn action is needed to save the next 'lost generation'. Psychosexual therapist Pauline Brown (2017)
  112. Young men who view more pornography experiencing erectile dysfunction, study says (Sex therapist Dr. Morgan Francis 2017)

The following excerpt from Park et al., 2016 provides empirical support for the existence of porn-induced sexual dysfunctions. This section also addresses two 2015 papers (neither were actual studies) which claim to have found little correlation between porn use and sexual dysfunctions.

1.2. Is Internet Pornography Use a Factor In Today's Sexual Dysfunctions?

Kinsey Institute researchers were among the first to report pornography-induced erectile-dysfunction (PIED) and pornography-induced abnormally low libido, in 2007 [27]. Half of subjects recruited from bars and bathhouses, where video pornography was “omnipresent”, were unable to achieve erections in the lab in response to video porn. In talking to the subjects, researchers discovered that high exposure to pornography videos apparently resulted in lower responsivity and an increased need for more extreme, specialized or “kinky” material to become aroused. The researchers actually redesigned their study to include more varied clips and permit some self-selection. A quarter of the participants’ genitals still did not respond normally [27].

Since then, evidence has mounted that Internet pornography may be a factor in the rapid surge in rates of sexual dysfunction. Nearly six out of 10 of 3962 visitors seeking help on the prominent “MedHelp.org ED Forum”, who mentioned their ages, were younger than 25. In that analysis of eight years of posts and comments, among words commonly linked with the mental aspect of ED (non-organic ED), “porn” appeared most frequently by far [28]. A 2015 study on high school seniors found that Internet pornography use frequency correlated with low sexual desire [29]. Of those who consumed Internet pornography more than once a week, 16% reported low sexual desire, compared with 0% in non-consumers (and 6% for those who consumed less than once a week). Another 2015 study of men (average age 41.5) seeking treatment for hypersexuality, who masturbated (“typically with very frequent pornography use”) seven or more hours per week, found that 71% had sexual dysfunctions, with 33% reporting difficulty orgasming [30]. Anxiety about sexual performance may impel further reliance on pornography as a sexual outlet. In a 2014 functional magnetic resonance imaging (fMRI) study, 11 of the 19 compulsive Internet pornography users (average age 25), whose brains were scanned for evidence of addiction, reported that as a result of excessive use of Internet pornography they had “experienced diminished libido or erectile function specifically in physical relationships with women (although not in relationship to the sexually explicit material)” [31]. Clinicians have also described pornography-related sexual dysfunctions, including PIED. For example, in his book The New Naked, urology professor Harry Fisch reported that excessive Internet pornography use impairs sexual performance in his patients [32], and psychiatry professor Norman Doidge reported in his book The Brain That Changes Itself that removal of Internet pornography use reversed impotence and sexual arousal problems in his patients [33]. In 2014, Bronner and Ben-Zion reported that a compulsive Internet pornography user whose tastes had escalated to extreme hardcore pornography sought help for low sexual desire during partnered sex. Eight months after stopping all exposure to pornography the patient reported experiencing successful orgasm and ejaculation, and succeeded in enjoying good sexual relations [34]. To date, no other researchers have asked men with sexual difficulties to remove the variable of Internet pornography use in order to investigate whether it is contributing to their sexual difficulties.

While such intervention studies would be the most illuminating, our review of the literature finds a number of studies that have correlated pornography use with arousal, attraction, and sexual performance problems [27,31,35,36,37,38,39,40,41,42,43], including difficulty orgasming, diminished libido or erectile function [27,30,31,35,43,44], negative effects on partnered sex [37], decreased enjoyment of sexual intimacy [37,41,45], less sexual and relationship satisfaction [38,39,40,43,44,45,46,47],a preference for using Internet pornography to achieve and maintain arousal over having sex with a partner [42], and greater brain activation in response to pornography in those reporting less desire for sex with partners [48]. Again, Internet pornography use frequency correlated with low sexual desire in high school seniors [29]. Two 2016 studies deserve detailed consideration here. The first study claimed to be the first nationally-representative study on married couples to assess the effects of pornography use with longitudinal data. It reported that frequent pornography consumption at Wave 1 (2006) was strongly and negatively related with participants’ marital quality and satisfaction with their sex life at Wave 2 (2012). The marriages most negatively affected were those of men who were viewing pornography at the highest frequencies (once a day or more). Assessing multiple variables, the frequency of pornography use in 2006 was the second strongest predictor of poor marital quality in 2012 [47]. The second study claimed to be the only study to directly investigate the relationships between sexual dysfunctions in men and problematic involvement in OSAs (online sexual activities). This survey of 434 men reported that lower overall sexual satisfaction and lower erectile function were associated with problematic Internet pornography use [44]. In addition, 20.3% of the men said that one motive for their pornography use was “to maintain arousal with my partner” [44]. In a finding that may indicate escalation of pornography use, 49% described sometimes “searching for sexual content or being involved in OSAs that were not previously interesting to them or that they considered disgusting” [44] (p.260). Finally, a significant percentage of the participants (27.6%) self-assessed their consumption of OSAs as problematic. While this rate of problematic pornography use may appear to be high, another 2016 study on 1298 men who had viewed pornography in the last six months reported that 28% of participants scored at or above the cutoff for hypersexuality disorder [49].

Our review also included two 2015 papers claiming that Internet pornography use is unrelated to rising sexual difficulties in young men. However, such claims appear to be premature on closer examination of these papers and related formal criticism. The first paper contains useful insights about the potential role of sexual conditioning in youthful ED [50]. However, this publication has come under criticism for various discrepancies, omissions and methodological flaws. For example, it provides no statistical results for the erectile function outcome measure in relation to Internet pornography use. Further, as a research physician pointed out in a formal critique of the paper, the papers’ authors, “have not provided the reader with sufficient information about the population studied or the statistical analyses to justify their conclusion” [51]. Additionally, the researchers investigated only hours of Internet pornography use in the last month. Yet studies on Internet pornography addiction have found that the variable of hours of Internet pornography use alone is widely unrelated to “problems in daily life”, scores on the SAST-R (Sexual Addiction Screening Test), and scores on the IATsex (an instrument that assesses addiction to online sexual activity) [52,53,54,55,56]. A better predictor is subjective sexual arousal ratings while watching Internet pornography (cue reactivity), an established correlate of addictive behavior in all addictions [52,53,54]. There is also increasing evidence that the amount of time spent on Internet video-gaming does not predict addictive behavior. “Addiction can only be assessed properly if motives, consequences and contextual characteristics of the behavior are also part of the assessment” [57]. Three other research teams, using various criteria for “hypersexuality” (other than hours of use), have strongly correlated it with sexual difficulties [15,30,31]. Taken together, this research suggests that rather than simply “hours of use”, multiple variables are highly relevant in assessment of pornography addiction/hypersexuality, and likely also highly relevant in assessing pornography-related sexual dysfunctions.

A second paper reported little correlation between frequency of Internet pornography use in the last year and ED rates in sexually active men from Norway, Portugal and Croatia [6]. These authors, unlike those of the previous paper, acknowledge the high prevalence of ED in men 40 and under, and indeed found ED and low sexual desire rates as high as 31% and 37%, respectively. In contrast, pre-streaming Internet pornography research done in 2004 by one of the paper’s authors reported ED rates of only 5.8% in men 35–39 [58]. Yet, based on a statistical comparison, the authors conclude that Internet pornography use does not seem to be a significant risk factor for youthful ED. That seems overly definitive, given that the Portuguese men they surveyed reported the lowest rates of sexual dysfunction compared with Norwegians and Croatians, and only 40% of Portuguese reported using Internet pornography “from several times a week to daily”, as compared with the Norwegians, 57%, and Croatians, 59%. This paper has been formally criticized for failing to employ comprehensive models able to encompass both direct and indirect relationships between variables known or hypothesized to be at work [59]. Incidentally, in a related paper on problematic low sexual desire involving many of the same survey participants from Portugal, Croatia and Norway, the men were asked which of numerous factors they believed contributed to their problematic lack of sexual interest. Among other factors, approximately 11%–22% chose “I use too much pornography” and 16%–26% chose “I masturbate too often” [60].

Again, intervention studies would be the most instructive. However, with respect to correlation studies, it is likely that a complex set of variables needs to be investigated in order to elucidate the risk factors at work in unprecedented youthful sexual difficulties. First, it may be that low sexual desire, difficulty orgasming with a partner and erectile problems are part of the same spectrum of Internet pornography-related effects, and that all of these difficulties should be combined when investigating potentially illuminating correlations with Internet pornography use.

Second, although it is unclear exactly which combination of factors may best account for such difficulties, promising variables to investigate in combination with frequency of Internet pornography use might include (1) years of pornography-assisted versus pornography-free masturbation; (2) ratio of ejaculations with a partner to ejaculations with Internet pornography; (3) the presence of Internet pornography addiction/hypersexuality; (4) the number of years of streaming Internet pornography use; (5) at what age regular use of Internet pornography began and whether it began prior to puberty; (6) trend of increasing Internet pornography use; (7) escalation to more extreme genres of Internet pornography, and so forth.

Park et al., 2016 continues with clinical support for the existence of porn-induced sexual dysfunctions

2. Clinical Reports

While correlation studies are easier to conduct, the difficulty in isolating the precise variables at work in the unprecedented rise of sexual dysfunction in men under 40 suggests that intervention studies (in which subjects removed the variable of Internet pornography use) would better establish whether there is a connection between its use and sexual difficulties. The following clinical reports demonstrate how asking patients with diverse and otherwise unexplained dysfunctions to eradicate Internet pornography use helps to isolate its effects on sexual difficulties. Below we report on three active duty servicemen. Two saw a physician for their non-organic erectile dysfunction, low sexual desire, and unexplained difficulty in achieving orgasm with partners. The first mentioned variables (1), (6) and (7), listed in the preceding paragraph. The second mentioned (6) and (7). Both were free of mental health diagnoses. We also report a third active duty serviceman who saw a physician for mental health reasons. He mentioned variable (6).

2.1. First Clinical Report

A 20-year old active duty enlisted Caucasian serviceman presented with difficulties achieving orgasm during intercourse for the previous six months. It first happened while he was deployed overseas. He was masturbating for about an hour without an orgasm, and his penis went flaccid. His difficulties maintaining erection and achieving orgasm continued throughout his deployment. Since his return, he had not been able to ejaculate during intercourse with his fiancée. He could achieve an erection but could not orgasm, and after 10–15 min he would lose his erection, which was not the case prior to his having ED issues. This was causing problems in his relationship with his fiancée.

Patient endorsed masturbating frequently for “years”, and once or twice almost daily for the past couple of years. He endorsed viewing Internet pornography for stimulation. Since he gained access to high-speed Internet, he relied solely on Internet pornography. Initially, “soft porn”, where the content does not necessarily involve actual intercourse, “did the trick”. However, gradually he needed more graphic or fetish material to orgasm. He reported opening multiple videos simultaneously and watching the most stimulating parts. When preparing for deployment about a year ago, he was worried about being away from partnered sex. So, he purchased a sex toy, which he described as a “fake vagina”. This device was initially so stimulating that he reached orgasm within minutes. However, as was the case with Internet pornography, with increased use, he needed longer and longer to ejaculate, and eventually he was unable to orgasm at all. Since returning from deployment, he reported continued masturbation one or more times per day using both Internet pornography and toy. Although physically and emotionally attracted to his fiancée, the patient reported that he preferred the device to actual intercourse because he found it more stimulating. He denied any other relationship issues. He also denied any personal and/or vocational stressors. He described his mood as “concerned” because he was worried there was something wrong with his genitals and he wanted his relationship with his fiancée to work. She was starting to think that he was no longer attracted to her.

Medically, he had no history of major illness, surgery, or mental health diagnoses. He was not taking any medications or supplements. He denied using tobacco products but drank a few drinks at parties once or twice a month. He had never blacked out from alcohol intoxication. He reported multiple sexual partners in the past, but since his engagement a year ago his fiancée had been his sole sexual partner. He denied a history of sexually transmitted diseases. On physical examination, his vital signs were all normal, and his genital exam was normal appearing without lesions or masses.

At the conclusion of the visit, it was explained to him that use of a sex toy had potentially desensitized his penile nerves and watching hardcore Internet pornography had altered his threshold for sexual stimulation. He was advised to stop using the toy and watching hardcore Internet pornography. He was referred to urology for further evaluation. By the time he was seen by the urologist a few weeks later, he had cut down on Internet pornography use significantly, although he said he could not completely stop. He ceased using the toy. He was having orgasms again through intercourse with his fiancée, and their relationship had improved. The urologist’s evaluation was normal.

2.2. Second Clinical Report

A 40-year old African American enlisted serviceman with 17 years of continuous active duty presented with difficulty achieving erections for the previous three months. He reported that when he attempted to have sexual intercourse with his wife, he had difficulty achieving an erection and difficulty maintaining it long enough to orgasm. Ever since their youngest child left for college, six months earlier, he had found himself masturbating more often due to increased privacy. He formerly masturbated every other week on average, but that increased to two to three times per week. He had always used Internet pornography, but the more often he used it, the longer it took to orgasm with his usual material. This led to him using more graphic material. Soon thereafter, sex with his wife was “not as stimulating” as before and at times he found his wife “not as attractive”. He denied ever having these issues earlier in the seven years of their marriage. He was having marital issues because his wife suspected he was having an affair, which he adamantly denied.

His medical history was only significant for hypertension, which was diagnosed more than two years earlier and had been well controlled with a diuretic: 25mg of chlorthalidone daily. He took no other medications or supplements. His only surgery was an appendectomy performed three years prior. He had no sexually transmitted diseases or mental health diagnoses. He endorsed smoking three packs of cigarettes per week for over ten years and drinking one to two drinks per week. Physical exam revealed vital signs within normal ranges, normal cardiovascular exam, and normal appearing genitals without lesions or masses.

At the end of the exam, his issues were attributed to heightened sexual stimulation threshold from exposure to hardcore Internet pornography and frequent masturbation. He was advised to stop watching hardcore Internet pornography and decrease masturbation frequency. Three months later, the patient reported that he tried “really hard” to avoid hardcore Internet pornography and to masturbate less, but he “just couldn’t do it”. He said whenever he was home alone, he found himself watching Internet pornography, which would eventually lead to masturbation. Not watching made him feel like he was “missing out”, which made him irritable and made him want to do it even more, to the point where he looked forward to his wife leaving the house. He was offered a referral to sex behavioral therapy, but he declined. He wanted to try to work on his behavior on his own.

2.3. Third Clinical Report

A 24-year old junior Enlisted Sailor was admitted to the inpatient mental health unit after a suicide attempt by overdose. During his evaluation and treatment he admitted to drinking alcohol even though he was advised to not use alcohol while being treated with antidepressant medications. His history and increasing tolerance were consistent with mild Alcohol Use Disorder due to his use while taking antidepressants. As part of the addictions portion of his history he was asked about gambling, Internet gaming and pornography addiction. He revealed that he had become concerned over his use of pornography, spending an excessive amount of time (5+ h a day) viewing online pornography for about six months. He also realized that he had diminished sexual interest in his wife, manifested by his inability to maintain sustained erections, preferring to view pornography where he had no erectile issues. When he became aware of his excessive use of pornography, he stopped viewing it completely, telling his interviewer he was afraid that if he viewed it to any extent he would find himself overusing it again. He reported that after he ceased using pornography his erectile dysfunction disappeared.

In summary, intervention studies designed to reveal causation by removing the variable of Internet pornography use are much needed to investigate unexplained sexual difficulties in Internet pornography users under 40. As suggested by our clinical reports, as well as the successes of clinicians Doidge [33] and Bronner and Ben-Zion [34] above, such research might ask study participants with possible PIED, difficulty achieving orgasm with a partner, and/or low sexual desire/satisfaction to eliminate Internet pornography.


SLIDE 24
 

Sexual enhancement drugs often stop working for these guys (if they ever did) - because their problem is not below the belt, where Viagra operates. Nor is their problem psychological. It’s due to physical and biochemical changes in the brain – addiction-related changes. Their numbed brains are sending weaker and weaker signals to their bananas.

ORIGINAL SUPPORT:

Original support for porn-induced ED can be found on slides 21, 22, 23, and 24. In summary, thousands of otherwise healthy young men (ages 16-40), with only one variable in common, years of masturbation to Internet porn, developed unexplained ED, delayed ejaculation, loss of attraction to real partners and anorgasmia. These young men differed in backgrounds, ethnicity, diets, exercise regimens, religious beliefs, moral beliefs, country of origin, education, economic status, on and on.

These young men could not achieve an erection without porn use, and gradually, some no longer achieved an erection with porn use. Many had seen multiple health-care practitioners and all had tried a number of approaches to cure their copulatory ED with no results. Most were very skeptical prior to healing their sexual problems that porn was the cause. The cause of their ED was not performance anxiety as they failed to achieve full erections while attempting to masturbate without porn (How do I know if my ED is porn-related? (TEST).

The claim that porn-induced ED is due to addiction-related brain changes was supported by the experiences of thousands of men who quit using porn and healed chronic sexual dysfunctions. Nearly every man who quit porn reported a similar constellation of physical and psychological symptoms, and a similar time-frame for the appearance of symptoms such as agitation, cravings, complete loss of libido. Many experienced withdrawal symptoms that parallel drug/alcohol withdrawal, such as cravings, anxiety, lethargy, depression, brain fog, sleeping abnormalities, restlessness, agitation, aches, pains, etc. (see: What does withdrawal from porn addiction look like?). Within 1-2 weeks, most subjects experience what is called "the flatline": low libido, perceived changes in genital sensation or size (see: HELP! I quit porn, but my potency, genital size, and/or libido are decreasing (the Flatline)). Recovery times vary: Between 2006-2010 most only needed 2-3 months, but lengths of recoveries have steadily increased over the intervening years. Some now need 6-12 months or longer. All of this suggests a very specific set of physical brain changes, and not psychological "issues."

UPDATED SUPPORT:

Updated support for the claims on slide 24 involves two parts:

  1. Excerpts from Is Internet Pornography Causing Sexual Dysfunctions? A Review with Clinical Reports (2016) summarizing the literature supporting the hypothesis that addiction-related brain changes are behind porn-induced sexual dysfunctions.
  2. Current list of studies linking porn use to sexual dysfunctions.

1. Excerpt from Is Internet Pornography Causing Sexual Dysfunctions? A Review with Clinical Reports (2016):

3.4. Neuroadaptations Related to Internet Pornography-Induced Sexual Difficulties

We hypothesize that pornography-induced sexual difficulties involve both hyperactivity and hypoactivity in the brain’s motivational system [72, 129] and neural correlates of each, or both, have been identified in recent studies on Internet pornography users [31, 48, 52, 53, 54, 86, 113, 114, 115, 120, 121, 130, 131, 132, 133, 134]. We have broken this portion of our discussion into three somewhat interrelated sections.

3.4.1. Increased Incentive Salience for Internet Pornography (Hyperactivity)

Hyperactivity refers to a sensitized, conditioned response to cues associated with use. Sensitized learning involves an enhanced mesolimbic dopamine system response that results in attribution of potentially pathological levels of incentive salience to cue-evoked seeking of drugs and natural rewards [135, 136, 137]. The mesolimbic dopamine system receives glutamate inputs from various cortical and limbic regions. Current theory suggests glutamatergic synapses associated with seeking and obtaining a particular reward undergo modifications, which enhance the response of the mesolimbic dopamine system to that same reward [100, 138]. These powerful new learned associations underlie the “incentive-salience” (or “incentive motivation”) theory of addiction.

With respect to our servicemen’s contact with partners, it is possible that as they sensitized their sexual arousal to Internet pornography, partnered sex no longer met their conditioned expectations and no longer triggered the release of sufficient dopamine to produce and sustain erections [50, 62, 139]. As Prause and Pfaus note, “Erectile problems may occur when real-life sexual stimulation does not match the broad content [accessible online]” [50]. Human and animal studies suggest that when expectations are unmet (a negative prediction error), activity in the mesolimbic dopamine pathway is inhibited [140, 141, 142, 143]. Addiction studies have reported that cues explicitly paired with the absence of drug reward can have marked inhibitory effects on dopamine release [72]. Consistent with a negative prediction error, Banca et al. reported a decrease in ventral striatal activity in response to the omission of an expected sexual image (following a conditioned cue) [86]. Banca et al. also reported that, compared to healthy controls, compulsive Internet pornography users had enhanced preference for conditioned cues (abstract patterns) related to sexual images [86]. This finding suggests that Internet pornography users can become sensitized to cues that are unrelated to sexual content, associations that can be extremely challenging to extinguish [87].

A 2014 fMRI study by Voon et al. provides support for the incentive-salience (sensitization) model with respect to compulsive Internet pornography users [31]. Compared to healthy controls, compulsive Internet pornography users had enhanced activity to sexually explicit films in the ventral striatum, amygdala and dorsal anterior cingulate cortex. This same core network is activated during cue reactivity and drug craving in substance abusers [144]. Voon et al. also reported that, “Compared to healthy volunteers, [compulsive internet pornography users] had greater subjective sexual desire or wanting to explicit cues and had greater liking scores to erotic [less explicit] cues, thus demonstrating a dissociation between wanting and liking” [31] (p. 2). In the incentive-sensitization model of addiction, dissociation between “wanting” and “liking” is considered an indication of pathological learning [106]. As the addiction to explicit Internet pornography progresses, motivation and cravings to use (“wanting”) increase, while pleasure from its use (“liking”) decreases. Here, Internet pornography viewers “liked” the tamer erotic stimuli, but “wanted” the explicit cues disproportionately. Similar to our servicemen, the majority of Voon et al.’s subjects (mean age 25) “had greater impairments of sexual arousal and erectile difficulties in intimate relationships but not with sexually explicit materials highlighting that the enhanced desire scores were specific to the explicit cues and not generalized heightened sexual desire” [31] (p. 5). A related study on most of the same subjects found enhanced attentional bias in compulsive Internet pornography users similar to that observed in studies of drug cues in addiction disorders [111]. The research team concluded that, “These studies together provide support for an incentive motivation theory of addiction underlying the aberrant response towards sexual cues in CSB [compulsive sexual behavior]” [111].

A 2015 fMRI study on male hypersexuals by Seok and Sohn replicated and expanded upon the findings of Voon et al. [31] and Mechelmans et al. [111] , just described [120]. Seok and Sohn reported that compared to controls hypersexuals had significantly greater brain activation when exposed to sexual images for 5 s. While Voon et al [31] examined cue-induced activity in the dACC-ventral striatal-amygdala functional network, Seok and Sohn assessed activity in the dorsolateral prefrontal cortex (DLPFC), caudate nucleus, inferior parietal lobe, dorsal anterior cingulate gyrus, and the thalamus. Seok and Sohn added that the severity of sexual addiction directly correlated with cue-induced activation of the DLPFC and thalamus. A third finding was that compared to controls hypersexuals had far greater DLPFC activation to sexual cues, yet far less DLPFC activation to neutral stimuli. This mirrors abnormal prefrontal cortex functioning in individuals with addiction where increased sensitivity to addiction cues is coupled with less interest in normal rewarding activities [145]. This finding aligns with our hypothesis that both hyperactivity and hypoactivity of the brain’s motivational system are involved in compulsive pornography use, and may be related to pornography-induced sexual dysfunctions.

A 2016 fMRI cue-reactivity study on male heterosexual pornography users expanded on previous findings [54]. Brand et al. reported that ventral striatum activity was greater for preferred pornographic material as compared to non-preferred pornographic material. In addition, stronger ventral striatum activity for preferred pornographic material was related to self-reported symptoms of addictive use of Internet pornography. In fact, symptoms of Internet pornography addiction (as assessed by the s-IATsex) were the only significant predictor of ventral striatum response to preferred versus non-preferred pornographic pictures. Other variables, such as weekly amount of cybersex, sexual excitability, hypersexual behavior in general, symptoms of depression and interpersonal sensitivity, and indicators of intensity of current sexual behavior, did not relate to cue-induced ventral striatum activity. Put simply, it was sensitization that best predicted symptoms of Internet pornography addiction. Brand et al. concluded that, “The findings emphasize parallels between IPA [internet pornography addiction] and other behavioral addictions and substance-related disorders” [54].

A 2016 fMRI study (Klucken et al.) [121] compared two groups of heterosexual males: subjects with compulsive sexual behaviors (CSB) and healthy controls. The mean time typically spent watching sexually explicit material weekly was 1187 min for the CSB group and 29 min for the control group. Researchers exposed all subjects to a conditioning procedure in which previously neutral stimuli (colored squares) predicted the presentation of an erotic picture. Compared to controls the subjects with CSB displayed increased activation of the amygdala during presentation of the conditioned cue predicting the erotic picture. This finding aligns with studies reporting increased amygdala activation when substance abusers are exposed to cues related to drug use [146]. Voon et al. also reported that explicit videos induced greater amygdala activation in CSB subjects than in healthy controls. This research converges with animal research linking the amygdala to appetitive conditioning. For example, stimulating opioid circuitry in the amygdala magnifies incentive salience intensity towards a conditioned cue, accompanied by a simultaneous reduction of the attractiveness of an alternative salient target [147]. While the CSB group in Klucken et al. [121] had greater amygdala activation to a cue predicting a sexual image, their subjective sexual arousal was no higher than controls. Interestingly, three of the twenty CSB subjects reported “orgasmic-erection disorder” when interviewed to screen for Axis I and Axis II diagnoses, while none of the control subjects reported sexual problems. This finding recalls Voon et al., in which CSB subjects had greater amygdala-ventral striatum-dACC activation to explicit sexual videos, yet 11 of 19 reported erectile or arousal difficulties with sexual partners. Klucken et al. also found decreased coupling between the ventral striatum and the prefrontal cortex in subjects with CSB compared with controls. Decreased ventral striatal-PFC coupling has been reported in substance disorders and is believed to be related to impaired impulse control [145].

A 2013 EEG study by Steele et al. reported higher P300 amplitude to sexual images, relative to neutral pictures, in individuals complaining of problems regulating their Internet pornography use [48]. Substance abusers also exhibit greater P300 amplitude when exposed to visual cues associated with their addiction [148]. In addition, Steele et al. reported a negative correlation between P300 amplitude and desire for sex with a partner [48]. Greater cue reactivity to Internet pornography paired with less sexual desire for partnered sex, as reported by Steele et al., aligns with the Voon et al. finding of “diminished libido or erectile function specifically in physical relationships with women” in compulsive Internet pornography users [31]. Supporting these findings, two studies assessing sexual desire and erectile function in “hypersexuals” and compulsive Internet pornography users reported associations between measures of hypersexuality, and reduced desire for partnered sex and sexual difficulties [15, 30]. Additionally, the 2016 survey of 434 men who viewed Internet pornography at least once in the last three months reported that problematic use was associated with higher levels of arousability, yet lower sexual satisfaction and poorer erectile function [44]. These results should be viewed in light of the multiple neuropsychology studies that have found that sexual arousal to Internet pornography cues and cravings to view pornography were related to symptom severity of cybersex addiction and self-reported problems in daily life due to excessive Internet pornography use [52, 53, 54, 113, 115, 149, 150]. Taken together, multiple and varied studies on Internet pornography users align with the incentive-salience theory of addiction, in which changes in the attraction value of an incentive correspond with changes in activation of regions of the brain implicated in the sensitization process [31, 106]. To sum up, in alignment with our hypothesis, various studies report that greater reactivity toward pornographic cues, cravings to view, and compulsive pornography use are associated with sexual difficulties and diminished sexual desire for partners.

3.4.2. Decreased Reward Sensitivity (Hypoactivity)

In contrast with the hyperactive response to Internet pornography cues just described, hypoactivity is a concomitant decrease in reward sensitivity to normally salient stimuli [70, 151, 152, 153], such as partnered sex [31, 48]. This decrease is also behind tolerance [70], and has been implicated in both substance and behavioral addictions [153, 154, 155, 156], including other types of Internet addictions [157, 158, 159].Our servicemen’s tolerance to Internet pornography increased fairly quickly, leading to viewing more extreme material. The fact that self-selected pornography video is more arousing than other pornography may contribute to habituation or tolerance [27, 75, 79, 81, 160]. For example, men who viewed a sexual film rather than a neutral film later showed less response to sexual images, a possible indication of habituation [161]. Not long after pornography videotapes became available, researchers also discovered that when viewers were given ad libitum access to pornography videotapes of varying themes they swiftly escalated to more extreme pornography [162]. The more video pornography viewed, the greater the desire for hardcore themes [27, 43, 162], indicative of declining sexual responsiveness. (Again, half of Kinsey Institute subjects who regularly consumed video pornography showed little erectile responsiveness in the lab, and reported a need for more novelty and variety [27], and half of pornography users surveyed recently also had moved to material that did not interest them previously or which they found disgusting [44] (p. 260).) In another study, sexual satisfaction with partners, as measured by affection, physical appearance, sexual curiosity, and sexual performance, was inversely related to pornography use [43]. In pair-bonding mammals extreme stimulation with amphetamine impairs pair-bonding via activation of mesolimbic dopamine receptors [163], and it is possible that today's supernormally stimulating Internet pornography brings about a similar effect in some users.

In line with the suggestion that some Internet pornography users’ reward systems may be hypoactive in response to partnered sex (as well as hyper-reactive to cues for Internet pornography use), a 2014 fMRI study of non-compulsive Internet pornography users by Kühn and Gallinat found that the right caudate of the striatum was smaller with more hours and years of Internet pornography viewing [134].The caudate appears to be involved in approach-attachment behaviors and is strongly implicated in motivational states associated with romantic love [164, 165]. Also, the greater the subjects’ Internet pornography use, the lower the activation in the left putamen when viewing sexually explicit still photos (0.530 s exposure). Activation of the putamen is associated with sexual arousal and penile tumescence [67, 166]. The authors suggested both findings were “in line with the hypothesis that intense exposure to pornographic stimuli results in a downregulation of the natural neural response to sexual stimuli” [134]. Interestingly, men with a “higher interest in degrading or extreme pornography” report greater concerns about their sexual performance, penis size, and ability to sustain an erection than other Internet pornography users [42]. As hypothesized, extreme pornography viewing may decrease sexual responsiveness in some users, thus driving a spiraling need for more extreme or novel material to perform [27]. Again, a 2016 study reported that half of men surveyed had moved to material “not previously interesting to them or that they considered disgusting” [44].

A 2015 EEG study by Prause et al. compared frequent viewers of Internet pornography (mean 3.8 h/week) who were distressed about their viewing to controls (mean 0.6 h/week) as they viewed sexual images (1.0 s exposure) [130]. In a finding that parallels Kühn and Gallinat, frequent Internet pornography viewers exhibited less neural activation (LPP) to sexual images than controls [130]. The results of both studies suggest that frequent viewers of Internet pornography require greater visual stimulation to evoke brain responses when compared with healthy controls or moderate Internet pornography users [167, 168]. In addition, Kühn and Gallinat reported that higher Internet pornography use correlated with lower functional connectivity between the striatum and the prefrontal cortex. Dysfunction in this circuitry has been related to inappropriate behavioral choices regardless of potential negative outcome [169]. In line with Kühn and Gallinat, neuropsychological studies report that subjects with higher tendency towards cybersex addiction have reduced executive control function when confronted with pornographic material [53, 114].

A 2015 fMRI study by Banca et al. reported that, compared to healthy controls, compulsive Internet pornography subjects had a greater choice preference for novel sexual images [86]. While novelty-seeking and sensation-seeking are associated with greater risk for several types of addictions [170], Banca et al. found no differences in sensation-seeking scores between compulsive Internet pornography users and healthy controls. The authors suggest that the preference for novelty was specific to Internet pornography use, and not generalized novelty- or sensation-seeking [86]. These results align with Brand et al. (2011), which found that “the number of sex applications used” was a significant predictor of addiction using the IATsex questionnaire, while personality facets were not related to cybersex addiction [53]. Banca et al. also reported that compulsive Internet pornography users showed greater habituation in the dorsal anterior cingulate cortex (dACC) to repeated viewing of the same sexual images [86]. Generally speaking, the degree of dACC habituation to sexual images was associated with greater preference for novel sexual stimuli [86]. The dACC is implicated in drug cue reactivity and craving, as well as the assessment of expected versus unexpected rewards [144, 171]. Voon et al. reported enhanced dACC activity in compulsive Internet pornography subjects in response to sexually explicit videos [31]. Banca et al.’s findings strongly suggest that greater novelty seeking in compulsive Internet pornography users is driven by more rapid habituation to sexual stimuli. The researchers concluded, “We show experimentally what is observed clinically that [compulsive internet pornography use] is characterized by novelty-seeking, conditioning and habituation to sexual stimuli in males” [86]. In a related study, many of these same subjects had also reported sexual arousal and erectile difficulties in partnered sexual activity, but not during Internet pornography use [31]. This implies that Internet pornography-induced sexual difficulties may be partly due to conditioned expectations of novelty that are not matched in partnered sexual activity. Taken together, Kühn and Gallinat [134], Prause et al. [130] and Banca et al. [86] demonstrated that frequent Internet pornography users exhibit (1) less brain activation in response to brief exposure to sexual images; (2) greater preference for novel sexual stimuli; (3) faster dACC habituation to sexual stimuli; and (4) less grey matter volume in the caudate. These findings support the hypothesis that Internet pornography use may decrease reward sensitivity, leading to increased habituation and tolerance as well as the need for greater stimulation to become sexually aroused.

Studies investigating psychogenic ED provide further support for the role of reward system hypoactivity in erectile dysfunction and low libido. Dopamine agonist apomorphine elicits penile erections in men with psychogenic ED [172]. When a 2003 fMRI study monitored brain patterns while men with psychogenic ED and potent controls viewed sexual films, those with psychogenic ED differed significantly from potent controls in the degree of activation of cortical and subcortical regions. When dopamine agonist apomorphine was administered to men with psychogenic ED, it produced brain activation patterns similar to those seen in potent controls: significantly increased striatal and hypothalamic activity combined with cortical deactivation [173]. Moreover, a 2012 MRI study found a strong correlation between a reduction of striatal and hypothalamic grey matter and psychogenic ED [174]. A 2008 study reported men with psychogenic ED exhibited blunted hypothalamic activity in response to a sexual film [175].

2. Studies linking porn use or porn addiction to ED, anorgasmia, low sexual desire, delayed ejaculation, and lower arousal to sexual stimuli.

Note: The debate about the existence of porn-induced sexual dysfunctions is over. The first 5 studies demonstrate causation as participants eliminated porn use and healed chronic sexual dysfunctions.

1) Is Internet Pornography Causing Sexual Dysfunctions? A Review with Clinical Reports (2016) - An extensive review of the literature related to porn-induced sexual problems. Involving 7 US Navy doctors (urologists, psychiatrists, and a MD with PhD in neuroscience) the review provides the latest data revealing a tremendous rise in youthful sexual problems. It also reviews the neurological studies related to porn addiction and sexual conditioning via Internet porn. The doctors provide 3 clinical reports of men who developed porn-induced sexual dysfunctions. Two of the three men healed their sexual dysfunctions by eliminating porn use. The third man experienced little improvement as he was unable to abstain from porn use. Excerpt:

Traditional factors that once explained men’s sexual difficulties appear insufficient to account for the sharp rise in erectile dysfunction, delayed ejaculation, decreased sexual satisfaction, and diminished libido during partnered sex in men under 40. This review (1) considers data from multiple domains, e.g., clinical, biological (addiction/urology), psychological (sexual conditioning), sociological; and (2) presents a series of clinical reports, all with the aim of proposing a possible direction for future research of this phenomenon. Alterations to the brain's motivational system are explored as a possible etiology underlying pornography-related sexual dysfunctions. This review also considers evidence that Internet pornography’s unique properties (limitless novelty, potential for easy escalation to more extreme material, video format, etc.) may be potent enough to condition sexual arousal to aspects of Internet pornography use that do not readily transition to real-life partners, such that sex with desired partners may not register as meeting expectations and arousal declines. Clinical reports suggest that terminating Internet pornography use is sometimes sufficient to reverse negative effects, underscoring the need for extensive investigation using methodologies that have subjects remove the variable of Internet pornography use.

2) Male masturbation habits and sexual dysfunctions (2016) - It's by a French psychiatrist who is the current president of the European Federation of Sexology. The paper revolves around his clinical experience with 35 men who developed erectile dysfunction and/or anorgasmia, and his therapeutic approaches to help them. The author states that most of his patients used porn, with several being addicted to porn. The abstract points to internet porn as the primary cause of the problems. 19 of the 35 men saw significant improvements in sexual functioning. The other men either dropped out of treatment or are still trying to recover. Excerpts:

Intro: Harmless and even helpful in his usual form widely practiced, masturbation in its excessive and pre-eminent form, generally associated today to pornographic addiction, is too often overlooked in the clinical assessment of sexual dysfunction it can induce.

Results: Initial results for these patients, after treatment to “unlearn” their masturbatory habits and their often associated addiction to pornography, are encouraging and promising. A reduction in symptoms was obtained in 19 patients out of 35. The dysfunctions regressed and these patients were able to enjoy satisfactory sexual activity.

Conclusion: Addictive masturbation, often accompanied by a dependency on cyber-pornography, has been seen to play a role in the etiology of certain types of erectile dysfunction or coital anejaculation. It is important to systematically identify the presence of these habits rather than conduct a diagnosis by elimination, in order to include habit-breaking deconditioning techniques in managing these dysfunctions.

3) Unusual masturbatory practice as an etiological factor in the diagnosis and treatment of sexual dysfunction in young men (2014) – One of the 4 case studies in this paper reports on a man with porn-induced sexual problems (low libido, fetishes, anorgasmia). The sexual intervention called for a 6-week abstinence from porn and masturbation. After 8 months the man reported increased sexual desire, successful sex and orgasm, and enjoying “good sexual practices. This is the first peer-reviewed chronicling of a recovery from porn-induced sexual dysfunctions. Excerpts from the paper:

"When asked about masturbatory practices, he reported that in the past he had been masturbating vigorously and rapidly while watching pornography since adolescence. The pornography originally consisted mainly of zoophilia, and bondage, domination, sadism, and masochism, but he eventually got habituated to these materials and needed more hardcore pornography scenes, including transgender sex, orgies, and violent sex. He used to buy illegal pornographic movies on violent sex acts and rape and visualized those scenes in his imagination to function sexually with women. He gradually lost his desire and his ability to fantasize and decreased his masturbation frequency."

In conjunction with weekly sessions with a sex therapist, the patient was instructed to avoid any exposure to sexually explicit material, including videos, newspapers, books, and internet pornography.

After 8 months, the patient reported experiencing successful orgasm and ejaculation. He renewed his relationship with that woman, and they gradually succeeded in enjoying good sexual practices.

4) How difficult is it to treat delayed ejaculation within a short-term psychosexual model? A case study comparison (2017) - This is a report on two "composite cases" illustrating the etiology and treatments for delayed ejaculation (anorgasmia). "Patient B" represented several young men treated by the therapist. Interestingly, the paper states that Patient B's "porn use had escalated into harder material", "as is often the case". The paper says that porn-related delayed ejaculation is not uncommon, and on the rise. The author calls for more research on porn's effects of sexual functioning. Patient B's delayed ejaculation was healed after 10 weeks of no porn. Excerpts:

The cases are composite cases taken from my work within the National Health Service in Croydon University Hospital, London. With the latter case (Patient B), it is important to note that the presentation reflects a number of young males who have been referred by their GPs with a similar diagnosis. Patient B is a 19-year-old who presented because he was unable to ejaculate via penetration. When he was 13, he was regularly accessing pornography sites either on his own through internet searches or via links that his friends sent him. He began masturbating every night while searching his phone for image…If he did not masturbate he was unable to sleep. The pornography he was using had escalated, as is often the case (see Hudson-Allez, 2010), into harder material (nothing illegal)…

Patient B was exposed to sexual imagery via pornography from the age of 12 and the pornography he was using had escalated to bondage and dominance by the age of 15.

We agreed that he would no longer use pornography to masturbate. This meant leaving his phone in a different room at night. We agreed that he would masturbate in a different way….

Patient B was able to achieve orgasm via penetration by the fifth session; the sessions are offered fortnightly in Croydon University Hospital so session five equates to approximately 10 weeks from consultation. He was happy and greatly relieved. In a three-month follow-up with Patient B, things were still going well.

Patient B is not an isolated case within the National Health Service (NHS) and in fact young men in general accessing psychosexual therapy, without their partners, speaks in itself to the stirrings of change.

This article therefore supports previous research that has linked masturbation style to sexual dysfunction and pornography to masturbation style. The article concludes by suggesting that the successes of psychosexual therapists in working with DE are rarely recorded in the academic literature, which has allowed the view of DE as a difficult disorder to treat remain largely unchallenged. The article calls for research into pornography usage and its effect on masturbation and genital desensitisation.

5) Situational Psychogenic Anejaculation: A Case Study (2014) - The details reveal a case of porn-induced anejaculation. The husband's only sexual experience prior to marriage was frequent masturbation to pornography - where he was able to ejaculate. He also reported sexual intercourse as less arousing than masturbation to porn. The key piece of information is that "re-training" and psychotherapy failed to heal his anejaculation. When those interventions failed, therapists suggested a complete ban on masturbation to porn. Eventually this ban resulted in successful sexual intercourse and ejaculation with a partner for the first time in his life. A few excerpts:

A is a 33-year-old married male with heterosexual orientation, a professional from a middle socio-economic urban background. He has had no premarital sexual contacts. He watched pornography and masturbated frequently. His knowledge about sex and sexuality was adequate. Following his marriage, Mr. A described his libido as initially normal, but later reduced secondary to his ejaculatory difficulties. Despite thrusting movements for 30-45 minutes, he had never been able to ejaculate or achieve orgasm during penetrative sex with his wife.

What didn't work:

Mr. A's medications were rationalized; clomipramine and bupropion were discontinued, and sertraline was maintained at a dose of 150 mg per day. Therapy sessions with the couple were held weekly for the initial few months, following which they were spaced to fortnightly and later monthly. Specific suggestions including focusing on sexual sensations and concentrating on the sexual experience rather than ejaculation were used to help reduce performance anxiety and spectatoring. Since problems persisted despite these interventions, intensive sex therapy was considered.

Eventually they instituted a complete ban on masturbation (which means he continued to masturbate to porn during the above failed interventions):

A ban on any form of sexual activity was suggested. Progressive sensate focus exercises (initially non-genital and later genital) were initiated. Mr. A described an inability to experience the same degree of stimulation during penetrative sex as compared to that which he experienced during masturbation. Once the ban on masturbation was enforced, he reported an increased desire for sexual activity with his partner.

After an unspecified amount of time, the ban on masturbation to porn lead to success:

Meanwhile, Mr. A and his wife decided to go ahead with Assisted Reproductive Techniques (ART) and underwent two cycles of intrauterine insemination. During a practice session, Mr. A ejaculated for the first time, following which he has been able to ejaculate satisfactorily during a majority of the couple's sexual interactions.

6) The Dual Control Model - The Role Of Sexual Inhibition & Excitation In Sexual Arousal And Behavior (2007) - Newly rediscovered and very convincing. In an experiment employing video porn, 50% of the young men couldn't become aroused or achieve erections with porn (average age was 29). The shocked researchers discovered that the men's erectile dysfunction was,

related to high levels of exposure to and experience with sexually explicit materials.

The men experiencing erectile dysfunction had spent a considerable amount of time in bars and bathhouses where porn was "omnipresent," and "continuously playing." The researchers stated:

Conversations with the subjects reinforced our idea that in some of them a high exposure to erotica seemed to have resulted in a lower responsivity to "vanilla sex" erotica and an increased need for novelty and variation, in some cases combined with a need for very specific types of stimuli in order to get aroused.

7) Exploring the Relationship Between Erotic Disruption During the Latency Period and the Use of Sexually Explicit Material, Online Sexual Behaviors, and Sexual Dysfunctions in Young Adulthood (2009) - This study examined correlations between current porn use (sexually explicit material - SEM) and sexual dysfunctions, and porn use during "latency period" (ages 6-12) and sexual dysfunctions. The average age of participants was 22. While current porn use correlated with sexual dysfunctions, porn use during latency (ages 6-12) had an even stronger correlation with sexual dysfunctions. A few excerpts:

Findings suggested that latency erotic disruption by way of sexually explicit material (SEM) and/or child sexual abuse may be associated to adult online sexual behaviors.

Furthermore, results demonstrated that latency SEM exposure was a significant predictor of adult sexual dysfunctions.

We hypothesized that exposure to latency SEM exposure would predict adult use of SEM. Study findings supported our hypothesis, and demonstrated that latency SEM exposure was a statistically significant predictor of adult SEM use. This suggested that individuals who were exposed to SEM during latency, may continue this behavior into adulthood. Study findings also indicated that latency SEM exposure was a significant predictor of adult online sexual behaviors.

8) Neural Correlates of Sexual Cue Reactivity in Individuals with and without Compulsive Sexual Behaviours (2014) - This fMRI study by Cambridge University found sensitization in porn addicts, which mirrored sensitization in drug addicts. It also found that porn addicts fit the accepted addiction model of wanting "it" more, but not liking "it" more. The researchers also reported that 60% of subjects (average age: 25) had difficulty achieving erections/arousal with real partners as a result of using porn, yet could achieve erections with porn. From the study ("CSB" is compulsive sexual behaviours):

CSB subjects reported that as a result of excessive use of sexually explicit materials.....[they] experienced diminished libido or erectile function specifically in physical relationships with women (although not in relationship to the sexually explicit material) ...

Compared to healthy volunteers, CSB subjects had greater subjective sexual desire or wanting to explicit cues and had greater liking scores to erotic cues, thus demonstrating a dissociation between wanting and liking. CSB subjects also had greater impairments of sexual arousal and erectile difficulties in intimate relationships but not with sexually explicit materials highlighting that the enhanced desire scores were specific to the explicit cues and not generalized heightened sexual desire.

9) Online sexual activities: An exploratory study of problematic and non-problematic usage patterns in a sample of men (2016) - This Belgian study from a leading research university found problematic Internet porn use was associated with reduced erectile function and reduced overall sexual satisfaction. Yet problematic porn users experienced greater cravings (as reported in many other studies). The study appears to report escalation, as 49% of the men viewed porn that "was not previously interesting to them or that they considered disgusting." (See studies reporting habituation/desensitization to porn and escalation of porn use.) Excerpts:

This study is the first to directly investigate the relationships between sexual dysfunctions and problematic involvement in OSAs. Results indicated that higher sexual desire, lower overall sexual satisfaction, and lower erectile function were associated with problematic OSAs (online sexual activities). These results can be linked to those of previous studies reporting a high level of arousability in association with sexual addiction symptoms (Bancroft & Vukadinovic, 2004; Laier et al., 2013; Muise et al., 2013).

Forty-nine percent mentioned at least sometimes searching for sexual content or being involved in OSAs that were not previously interesting to them or that they considered disgusting, and 61.7% reported that at least sometimes OSAs were associated with shame or guilty feelings.

10) Adolescents and web porn: a new era of sexuality (2015) - This Italian study analyzed the effects of Internet porn on high school seniors. It's co-authored by urology professor Carlo Foresta, president of the Italian Society of Reproductive Pathophysiology. The most interesting finding is that 16% of those who consume porn more than once a week report abnormally low sexual desire compared with 0% in non-consumers (and 6% for those who consume porn less than once a week). From the study:

21.9% define it as habitual, 10% report that it reduces sexual interest towards potential real-life partners, and the remaining, 9.1% report a kind of addiction. In addition, 19% of overall pornography consumers report an abnormal sexual response, while the percentage rose to 25.1% among regular consumers.

11) Patient Characteristics by Type of Hypersexuality Referral: A Quantitative Chart Review of 115 Consecutive Male Cases (2015) - A study on men (average age 41.5) with hypersexuality disorders, such as paraphilias, chronic masturbation or adultery. 27 of the men were classified as "avoidant masturbators," meaning they masturbated (typically with porn use) one or more hours per day, or more than 7 hours per week. 71% of the men who chronically masturbated to porn reported sexual functioning problems, with 33% reporting delayed ejaculation (a precursor to porn-induced ED). What sexual dysfunction do 38% of the remaining men have? The study doesn't say, and the authors have ignored repeated requests for details. Two primary choices for male sexual dysfunction are erectile dysfunction and low libido. It should be noted that the men were not asked about their erectile functioning without porn. This, if all their sexual activity involved masturbating to porn, and not sex with a partner, they might never realize they had porn-induced ED. (For reasons known only to her, Prause cites this paper as debunking the existence of porn-induced sexual dysfunctions.)

12) Men's Sexual Life and Repeated Exposure to Pornography. A New Issue? (2015) - Excerpts:

Mental health specialists should take in consideration the possible effects of pornography consumption on men sexual behaviors, men sexual difficulties and other attitudes related to sexuality. In the long term pornography seems to create sexual dysfunctions, especially the individual’s inability to reach an orgasm with his partner. Someone who spends most of his sexual life masturbating while watching porn engages his brain in rewiring its natural sexual sets (Doidge, 2007) so that it will soon need visual stimulation to achieve an orgasm.

Many different symptoms of porn consumption, such as the need to involve a partner in watching porn, the difficulty in reaching orgasm, the need for porn images in order to ejaculate turn into sexual problems. These sexual behaviors may go on for months or years and it may be mentally and bodily associated with the erectile dysfunction, although it is not an organic dysfunction. Because of this confusion, which generates embarrassment, shame and denial, lots of men refuse to encounter a specialist

Pornography offers a very simple alternative to obtain pleasure without implying other factors that were involved in human’s sexuality along the history of mankind. The brain develops an alternative path for sexuality which excludes “the other real person” from the equation. Furthermore, pornography consumption in a long term makes men more prone to difficulties in obtaining an erection in a presence of their partners.

13) The effects of sexually explicit material use on romantic relationship dynamics (2016) - As with many other studies, solitary porn users report poorer relationship and sexual satisfaction. Employing the Pornography Consumption Effect Scale (PCES), the study found that higher porn use was related to poorer sexual function, more sexual problems, and a "worse sex life." An excerpt describing the correlation between the PCES "Negative Effects" on "Sex Life" questions and frequency of porn use:

There were no significant differences for the Negative Effect Dimension PCES across the frequency of sexually explicit material use; however, there were significant differences on the Sex Life subscale where High Frequency Porn Users reported greater negative effects than Low Frequency Porn Users.

14) Altered Appetitive Conditioning and Neural Connectivity in Subjects With Compulsive Sexual Behavior (2016) - "Compulsive Sexual Behaviors" (CSB) means the men were porn addicts, because CSB subjects averaged nearly 20 hours of porn use per week. The controls averaged 29 minutes per week. Interestingly, 3 of the 20 CSB subjects mentioned to interviewers that they suffered from "orgasmic-erection disorder," while none of the control subjects reported sexual problems.

15) Brain Structure and Functional Connectivity Associated With Pornography Consumption: The Brain on Porn (2014) - This Max Planck study found 3 significant addiction-related brain changes correlating with the amount of porn consumed. It also found that the more porn consumed the less reward circuit activity in response to brief exposure (.530 second) to vanilla porn. In a 2014 article lead author Simone Kühn said:

We assume that subjects with a high porn consumption need increasing stimulation to receive the same amount of reward. That could mean that regular consumption of pornography more or less wears out your reward system. That would fit perfectly the hypothesis that their reward systems need growing stimulation.

A more technical description of this study from a review of the literature by Kuhn & Gallinat - Neurobiological Basis of Hypersexuality (2016):

The more hours participants reported consuming pornography, the smaller the BOLD response in left putamen in response to sexual images. Moreover, we found that more hours spent watching pornography was associated with smaller gray matter volume in the striatum, more precisely in the right caudate reaching into the ventral putamen. We speculate that the brain structural volume deficit may reflect the results of tolerance after desensitization to sexual stimuli.

16) Sexual Desire, not Hypersexuality, is Related to Neurophysiological Responses Elicited by Sexual Images (2013) - This EEG study was touted in the media as evidence against the existence of porn addiction. Not so. In line with the Cambridge University brain scan studies, this EEG study reported greater cue-reactivity to porn correlated with less desire for partnered sex. To put another way - individuals with more brain activation and cravings for porn would rather masturbate to porn than have sex with a real person. Puzzlingly, study spokesperson Prause claimed that porn users merely had "high libido," yet the results of the study say the exact opposite (their desire for partnered sex dropped in relation to signs of addiction). Five peer-reviewed papers explain the truth: 1, 2, 3, 4, 5. (See extensive YBOP critique for details.)

17) Modulation of Late Positive Potentials by Sexual Images in Problem Users and Controls Inconsistent with "Porn Addiction" (2015) - Another Prause EEG study, this time comparing the 2013 subjects from the above study to an actual control group. The results: compared to controls, "porn addicts" had less response to one-second exposure to photos of vanilla porn. Lead author Prause claimed these results debunk porn addiction. However, these findings align perfectly with Kühn & Gallinat (2014), which found that more porn use correlated with less brain activation in response to pictures of vanilla porn. Put simply, frequent porn users were desensitized to static images of vanilla porn. They were bored (habituated or desensitized). Six peer-reviewed papers agree that this study actually found desensitization or habituation (evidence of possible addiction) in frequent porn users: 1, 2, 3, 4. 5, 6. (Also see this extensive YBOP critique.) By the way, another EEG study also found that greater porn use in women correlated with less brain activation to porn.

18) Masturbation and Pornography Use Among Coupled Heterosexual Men With Decreased Sexual Desire: How Many Roles of Masturbation? (2015) - Masturbating to porn was related with decreased sexual desire and lower relationship intimacy. Excerpts:

Among men who masturbated frequently, 70% used pornography at least once a week. A multivariate assessment showed that sexual boredom, frequent pornography use, and low relationship intimacy significantly increased the odds of reporting frequent masturbation among coupled men with decreased sexual desire.

Among men [with decreased sexual desire] who used pornography at least once a week [in 2011], 26.1% reported that they were unable to control their pornography use. In addition, 26.7% of men reported that their use of pornography negatively affected their partnered sex and 21.1% claimed to have attempted to stop using pornography.

19) Use of pornography in a random sample of Norwegian heterosexual couples (2009) - Porn use correlated with more sexual dysfunctions in the male and negative self perception in the female. The couples who did not use porn had no sexual dysfunctions. A few excerpts from the study:

In couples where only one partner used pornography, we found more problems related to arousal (male) and negative (female) self-perception.

In those couples where one partner used pornography there was a permissive erotic climate. At the same time, these couples seemed to have more dysfunctions.

The couples who did not use pornography... may be considered more traditional in relation to the theory of sexual scripts. At the same time, they did not seem to have any dysfunctions.

Couples who both reported pornography use grouped to the positive pole on the ‘‘Erotic climate’’ function and somewhat to the negative pole on the ‘‘Dysfunctions’’ function.

20) Erectile Dysfunction, Boredom, and Hypersexuality among Coupled Men from Two European Countries (2015) - Survey reported a strong correlation between erectile dysfunction and measures of hypersexuality. The study omitted correlation data between erectile function and pornography use, but noted a significant correlation. An excerpt:

Among Croatian and German men, hypersexuality was significantly correlated with proneness to sexual boredom and more problems with erectile function.

21) An Online Assessment of Personality, Psychological, and Sexuality Trait Variables Associated with Self-Reported Hypersexual Behavior (2015) – Survey reported a common theme found in several other studies listed here: Compulsive porn users report greater arousability (cravings related to their addiction) combined with poorer sexual function (fear of experiencing erectile dysfunction).

"Hypersexual" behavior represents a perceived inability to control one's sexual behavior. To investigate hypersexual behavior, an international sample of 510 self-identified heterosexual, bisexual, and homosexual men and women completed an anonymous online self-report questionnaire battery.

Thus, the data indicated that hypersexual behavior is more common for males, and those who report being younger in age, more easily sexually excited, more sexually inhibited due to the threat of performance failure, less sexually inhibited due to the threat of performance consequences, and more impulsive, anxious, and depressed

22) Study sees link between porn and sexual dysfunction (2017) - The findings of an upcoming study presented at the American Urological Association's annual meeting. A few excerpts:

Young men who prefer pornography to real-world sexual encounters might find themselves caught in a trap, unable to perform sexually with other people when the opportunity presents itself, a new study reports. Porn-addicted men are more likely to suffer from erectile dysfunction and are less likely to be satisfied with sexual intercourse, according to survey findings presented Friday at the American Urological Association's annual meeting, in Boston.

"The rates of organic causes of erectile dysfunction in this age cohort are extremely low, so the increase in erectile dysfunction that we have seen over time for this group needs to be explained," Christman said. "We believe that pornography use may be one piece to that puzzle".

23) Associative pathways between pornography consumption and reduced sexual satisfaction (2017) - While it links porn use to lower sexual satisfaction, it also reported that frequency of porn use was related to a preference (or need?) for porn over sexual partners to achieve sexual arousal. An excerpt:

Finally, we found that frequency of pornography consumption was also directly related to a relative preference for pornographic rather than partnered sexual excitement. Participants in the present study primarily consumed pornography for masturbation. Thus, this finding could be indicative of a masturbatory conditioning effect (Cline, 1994; Malamuth, 1981; Wright, 2011). The more frequently pornography is used as an arousal tool for masturbation, the more an individual may become conditioned to pornographic as opposed to other sources of sexual arousal.

24) “I think it has been a negative influence in many ways but at the same time I can’t stop using it”: Self-identified problematic pornography use among a sample of young Australians (2017) - Online survey of Australians, aged 15-29. Those who had ever viewed pornography (n=856) were asked in an open-ended question: ‘How has pornography influenced your life?’

Among participants who responded to the open-ended question (n=718), problematic usage was self-identified by 88 respondents. Male participants who reported problematic usage of pornography highlighted effects in three areas: on sexual function, arousal and relationships. Responses included “I think it has been a negative influence in many ways but at the same time I can’t stop using it” (Male, Aged 18–19). Some female participants also reported problematic usage, with many of these reporting negative feelings like guilt and shame, impact on sexual desire and compulsions relating to their use of pornography. For example as one female participant suggested; “It makes me feel guilty, and I’m trying to stop. I don’t like how I feel that I need it to get myself going, it’s not healthy.” (Female, Aged 18–19)

25) Lecture describing upcoming studies - by Urology professor Carlo Foresta, president of the Italian Society of Reproductive Pathophysiology - The lecture contains the results of longitudinal and cross-sectional studies. One study involved a survey of high school teens (pages 52-53). The study reported that sexual dysfunction doubled between 2005 and 2013, with low sexual desire increasing 600%.

  • The percentage of teens that experienced alterations of their sexuality: 2004/05: 7.2%, 2012/13: 14.5%
  • The percentage of teens with low sexual desire: 2004/05: 1.7%, 2012/13: 10.3% (that's a 600% increase in 8 years)

Foresta also describes an upcoming study, "Sexuality media and new forms of sexual pathology sample 125 young males, 19-25 years" (Italian name - "Sessualità mediatica e nuove forme di patologia sessuale Campione 125 giovani maschi"). The results from the study (pages 77-78), which used the International Index of Erectile Function Questionnaire, found that regular porn users scored 50% lower on sexual desire domain and 30% lower of the erectile functioning domain.

26) (not peer-reviewed) Here's an article about an extensive analysis of comments and questions posted on MedHelp concerning erectile dysfunction. What's shocking is that 58% of the men asking for help were 24 or younger. Many suspected that internet porn could be involved as described in the results from the study -

The most common phrase is “erectile dysfunction” – which is mentioned more than three times as often as any other phrase – followed by “internet porn,” “performance anxiety,” and “watching porn.”

Clearly, porn is a frequently discussed subject: “I have been viewing internet pornography frequently (4 to 5 times a week) for the past 6 years,” one man writes. “I am in my mid-20s and have had a problem getting and maintaining an erection with sexual partners since my late teens when I first started looking at internet porn.”


SLIDE 25

As Dr. Foresta says, "It starts with lower reactions to porn sites. Then there is a general drop in libido, and in the end it becomes impossible to get an erection.”

3 take-aways from this:

  1. First, Foresta is describing a classic addiction process: gradual desensitization of the reward circuit.
  2. Second, internet porn is qualitatively different from Playboy. Widespread, youthful ED has never been seen before.
  3. Finally, ED is often the only symptom that gets these guys’ attention. The question is, "What less obvious symptoms are they missing?" Most don’t figure that out until after they quit.

--Here's a guy in his late twenties:

ORIGINAL SUPPORT:

Dr. Carlo Foresta is a urology professor, most recently President of the Italian Society of Reproductive Pathophysiology, and author of some 300 academic studies. The following articles support the above statements:

Again, Dr. Foresta's findings aligned with psychiatrist Norman Doidge's 2007 bestseller The Brain That Changes Itself, which also described tolerance (desensitization) and an increase in youthful ED. A relevant excerpt from chapter 5:

The changes I observed are not confined to a few people in therapy. A social shift is occurring. While it is usually difficult to get information about private sexual mores, this is not the case with pornography today, because its use is increasingly public. This shift coincides with the change from calling it "pornography" to the more casual term "porn." For his book on American campus life, I Am Charlotte Simmons, Tom Wolfe spent a number of years observing students on university campuses. In the book one boy, Ivy Peters, comes into the male residence and says, "Anybody got porn?"

Wolfe goes on, "This was not an unusual request. Many boys spoke openly about how they masturbated at least once every day, as if this were some sort of prudent maintenance of the psychosexual system." One of the boys tells Ivy Peters, "Try the third floor. They got some one-hand magazines up there." But Peters responds, "I've build up a tolerance to magazines...I need videos." Another boy says, "Oh, f'r Chrissake, I.P., it's ten o'clock at night. In another hour the cum dumpsters will start coming over here to spend the night...And you're looking for porn videos and a knuckle fuck." Then Ivy "shrugged and turned his palms up as if to say, 'I want porn. What's the big deal?'"

The big deal is his tolerance. He recognizes that he is like a drug addict who can no longer get high on the images that once turned him on. And the danger is that this tolerance will carry over into relationships, as it did in patients whom I was seeing, leading to potency problems and new, at times unwelcome, tastes. When pornographers boast that they are pushing the envelope by introducing new, harder themes, what they don't say is that they must, because their customers are building up a tolerance to the content. The back pages of men's risque magazines and Internet porn sites are filled with ads for Viagra-type drugs—medicine developed for older men with erectile problems related to aging and blocked blood vessels in the penis. Today young men who surf porn are tremendously fearful of impotence, or “erectile dysfunction” as it is euphemistically called. The misleading term implies that these men have a problem in their penises, but the problem is in their heads, in their sexual brain maps. The penis works fine when they use pornography. It rarely occurs to them that there may be a relationship between the pornography they are consuming and their impotence. (A few men, however, tellingly described their hours at computer porn sites as time spent "masturbating my brains out.")

As explained on Slide 23 YBOP has collected some 5,000 self-reports where men (and a few women) eliminated porn use and healed chronic sexual dysfunctions.

Porn recovery forums - Sections devoted to porn-induced sexual dysfunctions:

UPDATED SUPPORT:

This "updated" section addresses two claims from Slide 25:

  1. Desensitization or habituation plays a role in porn-induced sexual dysfunctions and escalation of porn use (tolerance - an addiction-related process).
  2. There has been an unprecedented rise in youthful erectile dysfunction (historically, ED rates in young men have been very low).

Desensitization (habituation) appears to play a role in porn-induced sexual dysfunctions and escalation of porn use (tolerance).

In the previous slide the excerpts from Park et al., 2016 provided support for the claim that "desensitization of the reward circuit" plays a role in porn-induced sexual dysfunctions. Desensitization or habituation leaves the individual less sensitive to pleasure, and often manifests as tolerance, which is the need for a higher dose or greater stimulation to achieve the same response. This is an addiction process. Desensitization can also take the form of escalating to new genres, sometimes harder and stranger, or even disturbing. This is because shock, surprise or anxiety can all elevate dopamine and waning sexual arousal.

Here's the 2017 evidence from PornHub that real sex is decreasingly interesting to porn users. Porn isn't enabling people to find their "real" tastes; it's driving them beyond normal into extreme novelty and "unreal" genres:

It appears that the trend is moving more toward fantasy than reality. ‘Generic’ porn is being replaced with fantasy specific or scenario specific scenes. Is this as a result of boredom or curiosity? One thing is certain; the typical ‘in-out, in-out’ no longer satisfies the masses, who are clearly looking for something different” notes Dr Laurie Betito.

As of 2017 six neurological studies have described desensitization or habituation occurring in internet porn users:

1) "Brain Structure and Functional Connectivity Associated With Pornography Consumption: The Brain on Porn" (Kuhn & Gallinat, 2014) - This Max Planck Institute fMRI study found less grey matter in the reward system (dorsal striatum) correlating with the amount of porn consumed. It also found that more porn use correlated with less reward circuit activation while briefly viewing sexual photos. Researchers believe their findings indicated desensitization, and possibly tolerance, which is the need for greater stimulation to achieve the same level of arousal. Lead author Simone Kühn said the following about her study:

That could mean that regular consumption of pornography more or less wears out your reward system. We assume that subjects with a high porn consumption need increasing stimulation to receive the same amount of reward. That would fit perfectly the hypothesis that their reward systems need growing stimulation.

Furthermore, in May, 2016. Kuhn & Gallinat published this review: Neurobiological Basis of Hypersexuality. In the review Kuhn & Gallinat describe their 2014 fMRI study:

In a recent study by our group, we recruited healthy male participants and associated their self-reported hours spent with pornographic material with their fMRI response to sexual pictures as well as with their brain morphology (Kuhn & Gallinat, 2014). The more hours participants reported consuming pornography, the smaller the BOLD response in left putamen in response to sexual images. Moreover, we found that more hours spent watching pornography was associated with smaller gray matter volume in the striatum, more precisely in the right caudate reaching into the ventral putamen. We speculate that the brain structural volume deficit may reflect the results of tolerance after desensitization to sexual stimuli.

2) "Novelty, conditioning and attentional bias to sexual rewards" (2015). A Cambridge University fMRI study reported greater habituation to sexual stimuli in compulsive porn users. An excerpt:

Online explicit stimuli are vast and expanding, and this feature may promote escalation of use in some individuals. For instance, healthy males viewing repeatedly the same explicit film have been found to habituate to the stimulus and find the explicit stimulus as progressively less sexually arousing, less appetitive and less absorbing (Koukounas and Over, 2000). ... We show experimentally what is observed clinically that Compulsive Sexual Behavior is characterized by novelty-seeking, conditioning and habituation to sexual stimuli in males.

From The Related Press Release:

The researchers found that sex addicts were more likely to choose the novel over the familiar choice for sexual images relative to neutral object images, whereas healthy volunteers were more likely to choose the novel choice for neutral human female images relative to neutral object images.

"We can all relate in some way to searching for novel stimuli online – it could be flitting from one news website to another, or jumping from Facebook to Amazon to YouTube and on," explains Dr Voon. "For people who show compulsive sexual behaviour, though, this becomes a pattern of behaviour beyond their control, focused on pornographic images."

In a second task, volunteers were shown pairs of images – an undressed woman and a neutral grey box – both of which were overlaid on different abstract patterns. They learned to associate these abstract images with the images, similar to how the dogs in Pavlov's famous experiment learnt to associate a ringing bell with food. They were then asked to select between these abstract images and a new abstract image.

This time, the researchers showed that sex addicts where more likely to choose cues (in this case the abstract patterns) associated with sexual and monetary rewards. This supports the notion that apparently innocuous cues in an addict's environment can 'trigger' them to seek out sexual images.

"Cues can be as simple as just opening up their internet browser," explains Dr Voon. "They can trigger a chain of actions and before they know it, the addict is browsing through pornographic images. Breaking the link between these cues and the behaviour can be extremely challenging."

The researchers carried out a further test where 20 sex addicts and 20 matched healthy volunteers underwent brain scans while being shown a series of repeated images – an undressed woman, a £1 coin or a neutral grey box.

They found that when the sex addicts viewed the same sexual image repeatedly, compared to the healthy volunteers they experienced a greater decrease of activity in the region of the brain known as the dorsal anterior cingulate cortex, known to be involved in anticipating rewards and responding to new events. This is consistent with 'habituation', where the addict finds the same stimulus less and less rewarding – for example, a coffee drinker may get a caffeine 'buzz' from their first cup, but over time the more they drink coffee, the smaller the buzz becomes.

This same habituation effect occurs in healthy males who are repeatedly shown the same porn video. But when they then view a new video, the level of interest and arousal goes back to the original level. This implies that, to prevent habituation, the sex addict would need to seek out a constant supply of new images. In other words, habituation could drive the search for novel images.

"Our findings are particularly relevant in the context of online pornography," adds Dr Voon. "It's not clear what triggers sex addiction in the first place and it is likely that some people are more pre-disposed to the addiction than others, but the seemingly endless supply of novel sexual images available online helps feed their addiction, making it more and more difficult to escape."

3) Modulation of late positive potentials by sexual images in problem users and controls inconsistent with "porn addiction (Prause et al., 2015.) The results: compared to controls "individuals experiencing problems regulating their porn viewing" had lower brain responses to one-second exposure to photos of vanilla porn. Lead author Prause claims these results "debunk porn addiction." If porn use had no effect on Prause et al's. subjects, we would expect controls and the frequent porn users to have the same LPP amplitude in response to sexual photos. Instead, the more frequent porn users had less brain activation (lower LPP). In reality, the findings of Prause et al. 2015 align perfectly with Kühn & Gallinat (2014), which found that more porn use correlated with less brain activation in response to pictures of vanilla porn (evidence consistent with an addiction process).

Prause's findings also align with Banca et al. 2015, which is #2 above. Moreover, another EEG study found that greater porn use in women correlated with less brain activation to porn. Lower EEG readings mean that subjects are paying less attention to the pictures. Put simply, frequent porn users were desensitized to static images of vanilla porn. They were bored (habituated or desensitized). Six peer-reviewed papers agree with this extensive critique that Prause actually found desensitization/habituation in frequent porn users: 1, 2, 3, 4, 5, 6.

4) Conscious and Non-Conscious Measures of Emotion: Do They Vary with Frequency of Pornography Use? (2017) – The study assessed porn user's responses (EEG readings & Startle Response) to various emotion-inducing images - including erotica. The authors believe two findings indicate habituation in the more frequent porn users. Excerpts:

4.1. Explicit Ratings

Interestingly, the high porn use group rated the erotic images as more unpleasant than the medium use group. The authors suggest this may be due to the relatively “soft-core” nature of the “erotic” images contained in the IAPS database not providing the level of stimulation that they may usually seek out, as it has been shown by Harper and Hodgins [58] that with frequent viewing of pornographic material, many individuals often escalate into viewing more intense material to maintain the same level of physiological arousal. The “pleasant” emotion category saw valence ratings by all three groups to be relatively similar with the high use group rating the images as slightly more unpleasant on average than the other groups. This may again be due to the “pleasant” images presented not being stimulating enough for the individuals in the high use group. Studies have consistently shown a physiological downregulation in processing of appetitive content due to habituation effects in individuals who frequently seek out pornographic material [3, 7, 8]. It is the authors’ contention that this effect may account for the results observed.

4.3. Startle Reflex Modulation (SRM)

The relative higher amplitude startle effect seen in the low and medium porn use groups may be explained by those in the group intentionally avoiding the use of pornography, as they may find it to be relatively more unpleasant. Alternatively, the results obtained also may be due to a habituation effect, whereby individuals in these groups do watch more pornography than they explicitly stated—possibly due to reasons of embarrassment among others, as habituation effects have been shown to increase startle eye blink responses [41, 42].

5) Exploring the Relationship between Sexual Compulsivity and Attentional Bias to Sex-Related Words in a Cohort of Sexually Active Individuals (2017) - This study replicates the findings of this 2014 Cambridge University study, which compared the attentional bias of porn addicts to healthy controls. The study correlated the "years of sexual activity" with 1) the sex addiction scores, and also 2) the results of the attentional bias task. Among those scoring high on sexual addiction, fewer years of sexual experience were related to greater attentional bias. So higher sexual compulsivity scores + fewer years of sexual experience = greater signs of addiction (greater attentional bias, or interference). But attentional bias declines sharply in the compulsive users, and disappears at the highest number of years of sexual experience. The authors concluded that this result could indicate that more years of "compulsive sexual activity" lead to greater habituation or a general numbing of the pleasure response (desensitization). An excerpt from the conclusion:

One possible explanation for these results is that as a sexually compulsive individual engages in more compulsive behaviour, an associated arousal template develops [36–38] and that over time, more extreme behaviour is required for the same level of arousal to be realised. It is further argued that as an individual engages in more compulsive behaviour, neuropathways become desensitized to more ‘normalised’ sexual stimuli or images and individuals turn to more ‘extreme’ stimuli to realise the arousal desired. This is in accordance with work showing that ‘healthy’ males become habituated to explicit stimuli over time and that this habituation is characterised by decreased arousal and appetitive responses [39]. This suggests that more compulsive, sexually active participants have become ‘numb’ or more indifferent to the ‘normalised’ sex-related words used in the present study and as such display decreased attentional bias, while those with increased compulsivity and less experience still showed interference because the stimuli reflect more sensitised cognition.

6) Neural Substrates of Sexual Desire in Individuals with Problematic Hypersexual Behavior (2015) - This Korean fMRI study replicates several other neurological studies on porn users: it reported cue-induced brain activation patterns and alterations in the prefrontal cortex that mirrored those occurring in drug addicts. In line with addiction model, sex addicts had greater cue-reactivity for sexual images, yet inhibited brain activation to other types of normally salient stimuli. Less neural response to normal everyday rewards is the primary indicator of desensitization.

Employing various methodologies and approaches, a diverse group of non-neurological studies have reported habituation to "regular porn" along with escalation into more extreme and unusual genres:

1) This was the very first study to ask porn users directly about escalation: "Online sexual activities: An exploratory study of problematic and non-problematic usage patterns in a sample of men" (2016). The study reports escalation, as 49% of the men reported viewing porn that was not previously interesting to them or that they once considered disgusting. An excerpt:

Forty-nine percent mentioned at least sometimes searching for sexual content or being involved in OSAs that were not previously interesting to them or that they considered disgusting.

This Belgian study also found problematic Internet porn use was associated with reduced erectile function and reduced overall sexual satisfaction. Yet problematic porn users experienced greater cravings. Interestingly, 20.3% of participants said that one motive for their porn use was "to maintain arousal with my partner." (OSA's = online sexual activity, which was porn for 99% of subjects). An excerpt:

This study is the first to directly investigate the relationships between sexual dysfunctions and problematic involvement in OSAs. Results indicated that higher sexual desire, lower overall sexual satisfaction, and lower erectile function were associated with problematic OSAs (online sexual activities). These results can be linked to those of previous studies reporting a high level of arousability in association with sexual addiction symptoms (Bancroft & Vukadinovic, 2004; Laier et al., 2013; Muise et al., 2013).

2) A 2017 study asked porn users directly about tolerance and withdrawal symptoms: The Development of the Problematic Pornography Consumption Scale (PPCS) (2017) - This paper developed and tested a problematic porn use questionnaire that was modeled after substance addiction questionnaires. Unlike previous porn addiction tests, this 18-item questionnaire assessed tolerance and withdrawal with the following 6 questions:

 

 

 

 

 

 

----------

 

 

 

 

 

 

Each question was scored from one to seven on a Likert scale: 1- Never, 2- Rarely, 3- Occasionally, 4- Sometimes, 5- Often, 6- Very Often, 7- All the Time. The graph below grouped porn users into 3 categories based on their total scores:  "Nonproblematic," "Low risk," and "At risk." The yellow line indicates no problems, which means that the "Low risk" and "At risk" porn users reported both tolerance and withdrawal. Put simply, both escalation (tolerance) and withdrawal are reported by some porn users.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3) The Dual Control Model: The Role Of Sexual Inhibition & Excitation In Sexual Arousal And Behavior, 2007. Indiana University Press, Editor: Erick Janssen, pp.197-222.  In an experiment employing video porn, 50% of the young men couldn't become aroused or achieve erections with porn (average age was 29). The shocked researchers discovered that the men's erectile dysfunction was,

 related to high levels of exposure to and experience with sexually explicit materials.

The men experiencing erectile dysfunction had spent a considerable amount of time in bars and bathhouses where porn was "omnipresent," and "continuously playing." The researchers stated:

Conversations with the subjects reinforced our idea that in some of them a high exposure to erotica seemed to have resulted in a lower responsivity to "vanilla sex" erotica and an increased need for novelty and variation, in some cases combined with a need for very specific types of stimuli in order to get aroused.

4) Out-of-control use of the internet for sexual purposes as behavioural addiction? An upcoming study (presented at the 4th International Conference on Behavioral Addictions, February 20–22, 2017) also directly asked about tolerance and withdrawal. It found both in "pornography addicts". 

Anna Ševčíková, Lukas Blinka and Veronika Soukalová

Masaryk University, Brno, Czech Republic

Background and aims: There is an ongoing debate whether excessive sexual behaviour should be understood as a form of behavioural addiction (Karila, Wéry, Weistein et al., 2014). The present qualitative study aimed at analysing the extent to which out-of-control use of the internet for sexual purposes (OUISP) may be framed by the concept of behavioural addiction among those individuals who were in treatment due to their OUISP.

Methods: We conducted in-depth interviews with 21 participants aged 22–54 years (Mage = 34.24 years). Using a thematic analysis, the clinical symptoms of OUISP were analysed with the criteria of behavioural addiction, with the special focus on tolerance and withdrawal symptoms (Griffiths, 2001).

Results: The dominant problematic behaviour was out-of-control online pornography use (OOPU). Building up tolerance to OOPU manifested itself as an increasing amount of time spent on pornographic websites as well as searching for new and more sexually explicit stimuli within the non-deviant spectrum. Withdrawal symptoms manifested themselves on a psychosomatic level and took the form of searching for alternative sexual objects. Fifteen participants fulfilled all of the addiction criteria.

Conclusions: The study indicates a usefulness for the behavioural addiction framework

Three papers suggest that porn users with no pedophilic interests can escalate to viewing child pornography.

5) First a review actually by UK psychiatrist): Internet pornography and paedophilia (2013). An excerpt:

Clinical experience and now research evidence are accumulating to suggest that the Internet is not simply drawing attention to those with existing paedophilic interests, but is contributing to the crystallisation of those interests in people with no explicit prior sexual interest in children.

The next two studies found that deviant (i.e., bestiality or minor) pornography users had a significantly younger onset of adult pornography use. Put simply, both studies link earlier onset of adult porn use to escalation to more extreme material.

6) Does deviant pornography use follow a Guttman-like progression?" (2013). An excerpt:

Results suggested deviant pornography use followed a Guttman-like progression in that individuals with a younger “age of onset” for adult pornography use were more likely to engage in deviant pornography (bestiality or child) compared to those with a later “age of onset”.

7) "Deviant Pornography Use: The Role of Early-Onset Adult Pornography Use and Individual Differences" (2016). An excerpt:

Results indicated that adult + deviant pornography users scored significantly higher on openness to experience and reported a significantly younger age of onset for adult pornography use compared to adult-only pornography users.

8) Exploring the effect of sexually explicit material on the sexual beliefs, understanding and practices of young men: A qualitative survey. A qualitative study reports escalation to extreme material. An excerpt:

Findings suggest that the key themes are: increased levels of availability of SEM, including an escalation in extreme content (Everywhere You Look) which are seen by young men in this study as having negative effects on sexual attitudes and behaviours (That's Not Good). Family or sex education may offer some ‘protection’ (Buffers) to the norms young people see in SEM. Data suggests confused views (Real verses Fantasy) around adolescents’ expectations of a healthy sex life (Healthy Sex Life) and appropriate beliefs and behaviours (Knowing Right from Wrong). A potential causal  pathway is described and areas of intervention highlighted.

10) Unusual masturbatory practice as an etiological factor in the diagnosis and treatment of sexual dysfunction in young men (2014). One of the 4 case studies in this paper reports on a man with porn-induced sexual problems (low libido, multiple porn fetishes, anorgasmia). The sexual intervention called for a 6-week abstinence from porn and masturbation. After 8 months the man reported increased sexual desire, successful sex and orgasm, and enjoying “good sexual practices." Excerpts from the paper documenting the patient's habituation and escalation into what he described as more extreme porn genres:

When asked about masturbatory practices, he reported that in the past he had been masturbating vigorously and rapidly while watching pornography since adolescence. The pornography originally consisted mainly of zoophilia, and bondage, domination, sadism, and masochism, but he eventually got habituated to these materials and needed more hardcore pornography scenes, including transgender sex, orgies, and violent sex. He used to buy illegal pornographic movies on violent sex acts and rape and visualized those scenes in his imagination to function sexually with women. He gradually lost his desire and his ability to fantasize and decreased his masturbation frequency.

An excerpt from the paper documents the patient's recovery from porn-induced sexual problems and fetishes:

In conjunction with weekly sessions with a sex therapist, the patient was instructed to avoid any exposure to sexually explicit material, including videos, newspapers, books, and internet pornography. After 8 months, the patient reported experiencing successful orgasm and ejaculation. He renewed his relationship with that woman, and they gradually succeeded in enjoying good sexual practices.

11)  Is Internet Pornography Causing Sexual Dysfunctions? A Review with Clinical Reports (2016) is an extensive review of the literature related to porn-induced sexual problems. Authored by US Navy doctors, the review provides the latest data revealing a tremendous rise in youthful sexual problems. It also reviews the neurological studies related to porn addiction and sexual conditioning via Internet porn. The doctors include 3 clinical reports of servicemen who developed porn-induced sexual dysfunctions. Two of the three servicemen healed their sexual dysfunctions by eliminating porn use while the third man experienced little improvement as he was unable to abstain from porn use. Two of the three servicemen reported habituation to current porn and escalation of porn use. The first serviceman describes his habituation to "soft porn" followed by escalation into more graphic and fetish porn: 

A 20-year old active duty enlisted Caucasian serviceman presented with difficulties achieving orgasm during intercourse for the previous six months. It first happened while he was deployed overseas. He was masturbating for about an hour without an orgasm, and his penis went flaccid. His difficulties maintaining erection and achieving orgasm continued throughout his deployment. Since his return, he had not been able to ejaculate during intercourse with his fiancée. He could achieve an erection but could not orgasm, and after 10–15 min he would lose his erection, which was not the case prior to his having ED issues.

Patient endorsed masturbating frequently for “years”, and once or twice almost daily for the past couple of years. He endorsed viewing Internet pornography for stimulation. Since he gained access to high-speed Internet, he relied solely on Internet pornography. Initially, “soft porn”, where the content does not necessarily involve actual intercourse, “did the trick”. However, gradually he needed more graphic or fetish material to orgasm. He reported opening multiple videos simultaneously and watching the most stimulating parts.

The second serviceman describes increased porn use and escalation into more graphic porn. Soon thereafter sex with his wife “not as stimulating as before":

A 40-year old African American enlisted serviceman with 17 years of continuous active duty presented with difficulty achieving erections for the previous three months. He reported that when he attempted to have sexual intercourse with his wife, he had difficulty achieving an erection and difficulty maintaining it long enough to orgasm. Ever since their youngest child left for college, six months earlier, he had found himself masturbating more often due to increased privacy. He formerly masturbated every other week on average, but that increased to two to three times per week. He had always used Internet pornography, but the more often he used it, the longer it took to orgasm with his usual material. This led to him using more graphic material. Soon thereafter, sex with his wife was “not as stimulating” as before and at times he found his wife “not as attractive”. He denied ever having these issues earlier in the seven years of their marriage. He was having marital issues because his wife suspected he was having an affair, which he adamantly denied.

12) Examining Correlates of Problematic Internet Pornography Use Among University Students (2016) Addictive use of internet porn, which is associated with poorer psychosocial functioning, emerges when people begin to use IP daily. Study reported that earlier age of exposure was related to escalation of use.

Age of first exposure to IP was found to be significantly correlated with frequent and addictive IP use (see Table 2). Participants who were exposed to IP at an earlier age were more likely to use IP more frequently, have longer IP sessions, and more likely to score higher on Adapted DSM-5 Internet Pornography Addiction Criteria and CPUI-COMP measures. Finally, total IP exposure was found to be significantly correlated with higher frequency of IP use. Participants who had longer total exposure to IP were also more likely to have more IP sessions per month.

13) The Relationship between Frequent Pornography Consumption, Behaviors, and Sexual Preoccupancy among Male Adolescents in Sweden (2017) - Porn use in 18-year old males was universal, and frequent porn users preferred hard-core porn. Does this indicate escalation of porn use?

Among frequent users, the most common type of pornography consumed was hard core pornography (71%) followed by lesbian pornography (64%), while soft core pornography was the most commonly selected genre for average (73%) and infrequent users (36%). There was also a difference between the groups in the proportion who watched hard core pornography (71%, 48%, 10%) and violent pornography (14%, 9%, 0%).

The authors suggest that frequent porn may ultimately lead to a preference for hard-core or violent pornography:

It is also noteworthy that a statistically significant relationship was found between fantasizing about pornography several times a week and watching hard core pornography. Since verbal and physical sexual aggression is so commonplace in pornography, what most adolescents considered hard core pornography could likely be defined as violent pornography. If this is the case, and in light of the suggested cyclical nature of sexual preoccupancy in Peter and Valkenburg, it may be that rather than ‘purging’ individuals of their fantasies and inclinations of sexual aggression, watching hard core pornography perpetuates them, thereby increasing the likelihood of manifested sexual aggression.

13) How difficult is it to treat delayed ejaculation within a short-term psychosexual model? A case study comparison (2017) - This is a report on two "composite cases" illustrating the causes and treatments for delayed ejaculation (anorgasmia). "Patient B" represented several young men treated by the therapist. Interestingly, the paper states that Patient B's "porn use had escalated into harder material", "as is often the case". The paper says that porn-related delayed ejaculation is not uncommon, and on the rise. The author calls for more research on porn's effects of sexual functioning. Patient B's delayed ejaculation was healed after 10 weeks of no porn. Excerpts related to escalation:

The cases are composite cases taken from my work within the National Health Service in Croydon University Hospital, London. With the latter case (Patient B), it is important to note that the presentation reflects a number of young males who have been referred by their GPs with a similar diagnosis. Patient B is a 19-year-old who presented because he was unable to ejaculate via penetration. When he was 13, he was regularly accessing pornography sites either on his own through internet searches or via links that his friends sent him. He began masturbating every night while searching his phone for image…If he did not masturbate he was unable to sleep. The pornography he was using had escalated, as is often the case (see Hudson-Allez, 2010), into harder material (nothing illegal)…

Patient B was exposed to sexual imagery via pornography from the age of 12 and the pornography he was using had escalated to bondage and dominance by the age of 15.

We agreed that he would no longer use pornography to masturbate. This meant leaving his phone in a different room at night. We agreed that he would masturbate in a different way….The article calls for research into pornography usage and its effect on masturbation and genital desensitisation.

14) Shifting Preferences In Pornography Consumption (1986) - Six weeks of exposure to nonviolent pornography resulted in subjects having little interest in vanilla porn, electing to almost exclusively watch "uncommon pornography" (bondage, sadomasochism, bestiality). An excerpt:

Male and female students and nonstudents were exposed to one hour of common, nonviolent pornography or to sexually and aggressively innocuous materials in each of six consecutive weeks. Two weeks after this treatment, they were provided with an opportunity to watch videotapes in a private situation. G-rated, R-rated, and X-rated programs were available. Subjects with considerable prior exposure to common, nonviolent pornography showed little interest in common, nonviolent pornography, electing to watch uncommon pornography (bondage, sadomasochism, bestiality) instead. Male nonstudents with prior exposure to common, nonviolent pornography consumed uncommon pornography almost exclusively. Male students exhibited the same pattern, although somewhat less extreme. This consumption preference was also in evidence in females, but was far less pronounced, especially among female students.

In the last 10 years an unprecedented rise in youthful erectile dysfunction has occurred (historically, ED rates have always been very low for men under 40).

In the 1940s, the Kinsey report concluded that the prevalence of ED was less than 1% in men younger than 30 years, less than 3% in those 30–45. In 2002 Dutch researchers did a meta-analysis of 6 high-quality ED studies. All of the studies reviewed from Europe (5) reported ED rates for men under 40 of approximately 2%. The sixth (US) reported erectile dysfunction rates of about 5%.

Studies assessing young male sexuality since 2009 report historic levels of sexual dysfunctions, and startling rates of the new scourge: low libido (documented in this lay article). Erectile dysfunction rates in these recent studies range from 14% to 35%, while rates for low libido (hypo-sexuality) range from 16% to 37%. Some studies involve teens and men 25 and under, while other studies involve men 40 and under. That's nearly a 1000% increase in youthful ED rates in the last 10-15 years. What variable has changed in the last 15 years that could account for this astronomical rise? Two excerpts from Park et al., 2016  (Introduction and Conclusion) exploring this tremendous rise in youthful sexual dysfunctions:

1.1. Trends in Sexual Dysfunction—Unanswered Questions

Up until the last decade, rates of ED were low in sexually active men under 40, and did not begin to rise steeply until thereafter [1,2]. A 1999 major cross-sectional study reported erectile dysfunction in 5%, and low sexual desire in 5% of sexually active men, ages 18 to 59 [3], and a 2002 meta-analysis of erectile-dysfunction studies reported consistent rates of 2% in men under 40 (except for the preceding study) [2]. These data were gathered before Internet “porn tube sites” enabled wide access to sexually explicit videos with no download required. The first of these “tube sites” appeared in September 2006 [4].

In contrast, recent studies on ED and low sexual desire document a sharp increase in prevalence of such dysfunctions in men under 40. One clear demonstration of this phenomenon relates to ED, and compares very large samples, all of which were assessed using the same (yes/no) question about ED as part of the Global Study of Sexual Attitudes and Behavior (GSSAB). In 2001–2002, it was administered to 13,618 sexually active men in 29 countries [5]. A decade later, in 2011, the same (yes/no) question from the GSSAB was administered to 2737 sexually active men in Croatia, Norway and Portugal [6]. The first group, in 2001–2002, were aged 40–80. The second group, in 2011, were 40 and under. Based on the findings of historical studies cited earlier, older men would be expected to have far higher ED rates than the negligible rates of younger men [2,7]. However, in just a decade, things changed radically. The 2001–2002 rates for older men 40–80 were about 13% in Europe [5]. By 2011, ED rates in young Europeans, 18–40, ranged from 14%–28% [6].

In the last few years, research using a variety of assessment instruments has revealed further evidence of an unprecedented increase in sexual difficulties among young men. In 2012, Swiss researchers found ED rates of 30% in a cross-section of Swiss men aged 18–24 using the International Index of Erectile Function (IIEF-5) [8]. A 2013 Italian study reported one in four patients seeking help for new onset ED were younger than 40, with rates of severe ED nearly 10% higher than in men over 40 [9]. A 2014 study on Canadian adolescents reported that 53.5% of males aged 16–21 had symptoms indicative of a sexual problem [10]. Erectile dysfunction was the most common (26%), followed by low sexual desire (24%), and problems with orgasm (11%). The results took the authors by surprise, “It is unclear why we found such high rates overall, but especially the high rates among both male and female participants rather than female participants alone, as is common in the adult literature” [10] (p.638). A 2016 study by this same group assessed sexual problems in adolescents (16–21 years) in five waves over a two-year period. For males, persistent problems (in at least one wave) were low sexual satisfaction (47.9%), low desire (46.2%), and problems in erectile function (45.3%). The researchers noted that over time rates of sexual problems declined for females, but not for males [11]. A 2014 study of new diagnoses of ED in active duty servicemen reported that rates had more than doubled between 2004 and 2013 [12]. Rates of psychogenic ED increased more than organic ED, while rates of unclassified ED remained relatively stable [12]. A 2014 cross-sectional study of active duty, relatively healthy, male military personnel aged 21–40 employing the five-item IIEF-5 found an overall ED rate of 33.2% [13], with rates as high as 15.7% in individuals without posttraumatic stress disorder [14]. The researchers also noted that sexual dysfunctions are subject to underreporting biases related to stigmatization [14], and that only 1.64% of those with ED had sought prescriptions for phosphodiesterase-5 inhibitors through the military [13]. A second analysis of the military cross-sectional data revealed that the increased sexual functioning problems were associated with “sexual anxiety” and “male genital self-image” [14]. A 2015 “Brief Communication” reported ED rates as high as 31% in sexually active men and low sexual desire rates as high as 37% [6]. Finally, another 2015 study on men (mean age approximately 36), reported that ED accompanied by a low desire for partnered sex is now a common observation in clinical practice among men seeking help for their excessive sexual behavior, who frequently “use pornography and masturbate” [15].

Traditionally, ED has been seen as an age-dependent problem [2], and studies investigating ED risk factors in men under 40 have often failed to identify the factors commonly associated with ED in older men, such as smoking, alcoholism, obesity, sedentary life, diabetes, hypertension, cardiovascular disease, and hyperlipidemia [16]. ED is usually classified as either psychogenic or organic. Psychogenic ED has been related to psychological factors (e.g., depression, stress, generalized anxiety, or performance anxiety) while organic ED has been attributed to physical conditions (e.g., neurological, hormonal, anatomical, or pharmacologic side effects) [17]. For men under 40 the most common diagnosis is psychogenic ED, and researchers estimate that only 15%–20% of cases are organic in origin [18].

However, none of the familiar correlative factors suggested for psychogenic ED seem adequate to account for a rapid many-fold increase in youthful sexual difficulties. For example, some researchers hypothesize that rising youthful sexual problems must be the result of unhealthy lifestyles, such as obesity, substance abuse and smoking (factors historically correlated with organic ED). Yet these lifestyle risks have not changed proportionately, or have decreased, in the last 20 years: Obesity rates in U.S. men aged 20–40 increased only 4% between 1999 and 2008 [19]; rates of illicit drug use among US citizens aged 12 or older have been relatively stable over the last 15 years [20]; and smoking rates for US adults declined from 25% in 1993 to 19% in 2011 [21]. Other authors propose psychological factors. Yet, how likely is it that anxiety and depression account for the sharp rise in youthful sexual difficulties given the complex relationship between sexual desire and depression and anxiety? Some depressed and anxious patients report less desire for sex while others report increased sexual desire [22,23,24,25]. Not only is the relationship between depression and ED likely bidirectional and co-occurring, it may also be the consequence of sexual dysfunction, particularly in young men [26]. While it is difficult to quantify rates of other psychological factors hypothesized to account for the sharp rise in youthful sexual difficulties, such as stress, distressed relationships, and insufficient sex education, how reasonable is it to presume that these factors are (1) not bidirectional and (2) have mushroomed at rates sufficient to explain a rapid multi-fold increase in youthful sexual difficulties, such as low sexual desire, difficulty orgasming, and ED?

4. Conclusions and Recommendations

Traditional factors that once explained sexual difficulties in men appear insufficient to account for the sharp rise in sexual dysfunctions and low sexual desire in men under 40. Both the literature and our clinical reports underscore the need for extensive investigation of Internet pornography's potential effects on users, ideally by having subjects remove the variable of Internet pornography in order to demonstrate potential effects of behavioral modification. A 2015 study, for example, found that rates of delay discounting (choosing immediate gratification over delayed rewards of greater value) decreased when healthy participants endeavored to give up Internet pornography use for just three weeks (compared with a control group who endeavored to give up their favorite food for the same time period) [75]. Both behavior and the nature of the stimuli given up were key variables.

While non-organic sexual dysfunctions have been presumed psychological in origin, and therefore the province of mental health experts, the unexplained sexual dysfunctions now rising sharply in young men (ED, difficulty orgasming, low sexual desire) are, to the extent they are reversible by quitting Internet pornography, not arising from “performance anxiety” (that is, psychosexual dysfunction, ICD-9 code 302.7), although performance anxiety may certainly accompany them. Future researchers will need to take into account the unique properties and impact of today's streaming Internet delivery of pornography. In addition, Internet pornography consumption during early adolescence, or before, may be a key variable.

Our review and clinical reports also highlight the need for validated screening tools to identify the possible presence of non-organic sexual difficulties, as well as Internet pornography-related difficulties in otherwise healthy men. The latter may often be reversible simply by modifying behavior. Because Internet pornography-related sexual difficulties are not yet specifically encompassed in an official diagnosis, healthcare providers do not routinely screen for them, leaving patients vulnerable. In this regard, in order to assess patients correctly, it may be critical to distinguish pornography-free from pornography-assisted masturbation. Traditionally, if patients had no difficulty with erections, arousal and climax while masturbating, but reported problems during partnered sex, they were presumed to have psychogenic, not organic, problems. However, young patients asked about their capabilities may assume “masturbation” refers to “masturbation with the aid of internet pornography”, and therefore be assessed as having “performance anxiety”, when their partnered-sex difficulties are actually Internet pornography-related. One simple test healthcare providers might employ is to ask, “whether the patient can achieve and sustain a satisfactory erection (and climax as desired) when masturbating without using Internet pornography”. If he cannot, but can easily achieve these goals with Internet pornography, then his sexual dysfunction may be associated with its use. Without employing such a test, there is a risk of false diagnoses of “performance anxiety”, and a consequent risk of prescribing needless psychoactive medications and (ultimately perhaps ineffective) phosphodiesterase-5 inhibitors. Other indications of Internet pornography-related performance difficulties may be loss of nocturnal erections and/or spontaneous erections. Additional research in this area is warranted.

Additionally, while healthcare providers must certainly screen for relationship problems, low self-esteem, depression, anxiety, PTSD, stress and other mental health problems, they should be cautious of assuming that poor mental health is the cause of otherwise unexplained sexual dysfunction in men under 40. The relationship between these factors and sexual dysfunction in young men may be bidirectional and co-occurring, or may be the consequence of sexual dysfunction [26].


SLIDE 26

I've been to psychologists and psychiatrists for the last 8 years. Have been diagnosed with depression, severe social anxiety, severe memory impairment, and a few others. Have tried Effexor, Ritalin, Xanax, and Paxil. Dropped out of two different colleges. Been fired twice. Used pot to calm my social anxiety. I've been approached by quite a few women (I guess due to looks/status), but they quickly flew away due to my incredible weirdness. I've been a hardcore porn addict since about 14.

For the last two years I've been experimenting, and finally realized porn was an issue. I stopped it completely two months ago. It has been very difficult, but so far incredibly worth it. I've since quit my remaining medication.”

ORIGINAL SUPPORT:

This is an anecdote. However, I had seen hundreds just like it by the time I did The Great Porn Experiment. Empirical support for "arousal addiction" (internet porn, internet gaming) inducing or exacerbating mental and emotional conditions was provided on Slide 11. See Slide 21 for links to forums were men eliminated porn and described remission of similar symptoms. See the following articles (and the comments sections below the articles) for additional self-reports similar to the anecdote featured in the talk.

UPDATED SUPPORT:

Empirical and clinical support for "arousal addiction" (internet porn, internet gaming) inducing or exacerbating mental and emotional conditions was provided under Slide 11.

It must be noted that since 2011 hundreds of articles have been published pointing to an unprecedented rise in adolescent mental health problems (depression, anxiety, social anxiety). Many of the experts quoted in the articles cite internet use and widespread adoption of smartphones as the primary reason for the increase in mental health problems. A few such articles:

Why Are More American Teenagers Than Ever Suffering From Severe Anxiety? (2017) – An excerpt:

When I asked Eken about other common sources of worry among highly anxious kids, she didn’t hesitate: social media. Anxious teenagers from all backgrounds are relentlessly comparing themselves with their peers, she said, and the results are almost uniformly distressing.

Anxious kids certainly existed before Instagram, but many of the parents I spoke to worried that their kids’ digital habits — round-the-clock responding to texts, posting to social media, obsessively following the filtered exploits of peers — were partly to blame for their children’s struggles. To my surprise, anxious teenagers tended to agree. At Mountain Valley, I listened as a college student went on a philosophical rant about his generation’s relationship to social media. “I don’t think we realize how much it’s affecting our moods and personalities,” he said. “Social media is a tool, but it’s become this thing that we can’t live without but that’s making us crazy.”

In his case, he had little doubt that social media made him more self-conscious. “In high school, I’d constantly be judging my self-worth online,” he told me, recalling his tortured relationship with Facebook. “I would think, Oh, people don’t want to see me on their timeline.”

While smartphones can provoke anxiety, they can also serve as a handy avoidance strategy. At the height of his struggles, Jake spent hours at a time on his phone at home or at school. “It was a way for me not to think about classes and college, not to have to talk to people,” he said. Jake’s parents became so alarmed that they spoke to his psychiatrist about it and took his phone away a few hours each night.

At a workshop for parents last fall at the NW Anxiety Institute in Portland, Ore., Kevin Ashworth, the clinical director, warned them of the “illusion of control and certainty” that smartphones offer anxious young people desperate to manage their environments. “Teens will go places if they feel like they know everything that will happen, if they know everyone who will be there, if they can see who’s checked in online,” Ashworth told the parents. “But life doesn’t always come with that kind of certainty, and they’re never practicing the skill of rolling with the punches, of walking into an unknown or awkward social situation and learning that they can survive it.”

Jean Twenge, a professor of psychology at San Diego State University who researches adolescent mental health and psychological differences among generations, used to be skeptical of those who sounded an alarm about teenage internet use. “It seemed like too easy an explanation for negative mental-health outcomes in teens, and there wasn’t much evidence for it,” she told me. She searched for other possible explanations, including economic ones. But the timing of the spike in anxious and depressed teenagers since 2011, which she called one of the sharpest and most significant she has seen, is “all wrong,” she said. “The economy was improving by the time the increase started.”

The more she looked for explanations, the more she kept returning to two seemingly unrelated trend lines — depression in teenagers and smartphone adoption. (There is significantly more data about depression than anxiety.) Since 2011, the trend lines increased at essentially the same rate. In her recent book “iGen,” and in an article in The Atlantic, Twenge highlights a number of studies exploring the connection between social media and unhappiness. “The use of social media and smartphones look culpable for the increase in teen mental-health issues,” she told me. “It’s enough for an arrest — and as we get more data, it might be enough for a conviction.”

Teenagers’ anxiety and depression on the rise (2017) – An excerpt:

Most parents can easily identify one of the biggest 21st-century culprits affecting teen mental health: social media. Scientists are discovering an increasing number of troubling links between social networking and mental health challenges. That’s not surprising: Teens are particularly susceptible to peer pressure, which puts them at risk for experiencing or exacerbating mental health issues with more time on social media sites.

Studies show that increased Facebook use is correlated with low self-esteem and decreased life satisfaction. There’s also a biological component: The constant overstimulation created by social networking shifts the nervous system into fight-or-flight mode, which makes teen depression and anxiety worse. And the problem isn’t going away soon: Seventy-six percent of teens use social media, and 50 percent of teens feel they are addicted to their mobile devices.

Have Smartphones Destroyed a Generation? (2017)

Psychologically, however, they are more vulnerable than Millennials were: Rates of teen depression and suicide have skyrocketed since 2011. It’s not an exaggeration to describe iGen as being on the brink of the worst mental-health crisis in decades. Much of this deterioration can be traced to their phones.

Social-networking sites like Facebook promise to connect us to friends. But the portrait of iGen teens emerging from the data is one of a lonely, dislocated generation.

Of course, these analyses don’t unequivocally prove that screen time causes unhappiness; it’s possible that unhappy teens spend more time online. But recent research suggests that screen time, in particular social-media use, does indeed cause unhappiness.

So is depression. Once again, the effect of screen activities is unmistakable: The more time teens spend looking at screens, the more likely they are to report symptoms of depression.

Teens who spend three hours a day or more on electronic devices are 35 percent more likely to have a risk factor for suicide, such as making a suicide plan. (That’s much more than the risk related to, say, watching TV.) One piece of data that indirectly but stunningly captures kids’ growing isolation, for good and for bad: Since 2007, the homicide rate among teens has declined, but the suicide rate has increased. As teens have started spending less time together, they have become less likely to kill one another, and more likely to kill themselves. In 2011, for the first time in 24 years, the teen suicide rate was higher than the teen homicide rate.


SLIDE 27
 

“My anxiety is nonexistent. My memory and focus are sharper than they've ever been. I feel like a huge "chick magnet," and my ED is gone too. I seriously think I had a rebirth – a second chance at life.”

ORIGINAL SUPPORT:

See preceding slide.

UPDATED SUPPORT:

Empirical support for the existence of porn-induced sexual dysfunctions was provided under Slides 21 through 25.

As described, experts blame the widespread adoption of smartphones and increased internet use for the unprecedented jump in youthful mental disorders. During this same time period ED rates have skyrocketed among young men.

Moreover, the percentage of US high school students who are currently sexually active (had sexual intercourse during the past three months) has decreased from 38% in 1991 to 30% in 2015. In tech-loving Japan a 2010 survey found that 36% of Japanese men aged 16 to 19 had no interest in sex, double the figure from 2008 (what is the figure in 2017?). The following infographic puts this all into perspective:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


SLIDE 28

This is why pockets of guys are appearing all over the web. On bodybuilding sites, pick-up-artist sites, sports sites - wherever men congregate. They are seeking a neurochemical rebirth. Here's a group on Reddit.com, who call themselves "fapstronauts."  "Fapping" is slang for solo sex – but they really mean giving up porn. They have added 2000 members since this picture was taken one month ago.

ORIGINAL SUPPORT:

Original source  - NoFap subreddit

See Slide 21 for links to forums were men eliminated porn and described remission of similar symptoms.

UPDATED SUPPORT:

NoFap subreddit now has 270,000+ members.

NoFap.com, which was started by the same young man, now has over 100,000 members


SLIDE 29
 

This movement to unhook from porn is growing. In fact, groups of are springing up across the web…in Europe too. But, there’s a bizarre fly in the ointment.

ORIGINAL SUPPORT:

See Slide 21 for links to forums were men eliminated porn and described remission of similar symptoms.

UPDATED SUPPORT:

The following Google trends graph reveals how popular "NoFap" has become since January, 2011:

 

 

 

 

 

 

 

 

 

 

 


SLIDE 30
 

Guys in their early twenties aren’t regaining erectile health as quickly as older guys. How can a 50-year-old get his mojo back faster than a 20-something? Answer: even though the older guys used porn far longer, they didn’t start with today’s highspeed internet porn. We know this is the key variable – because older users don’t develop porn-related sexual problems until after they get high-speed Internet.

ORIGINAL SUPPORT:

Slides 21 through 25 provide clinical and empirical support for the existence of porn-induced sexual dysfunctions. Original support for younger men taking longer to regain sexual functioning and libido can be found in porn-induced ED recovery stories:

UPDATED SUPPORT:

Unfortunately, Slide 30 is out of date. Many young men with porn-induced ED now need 6 months, 9 months, even 1-2 years to regain sexual functioning. In the intervening years YBOP published articles describing this disturbing trend (the articles include numerous "long recovery stories"):

No study has yet to compare porn-induced ED recovery times for different age groups.


SLIDE 31

Today’s young teens start high-speed internet porn when their brains are at their peak of dopamine production and neuroplasticity. This is also when they are most vulnerable to addiction. But there’s another risk:

ORIGINAL SUPPORT:

By 2012 it was well established that teens are the group most vulnerable to addiction. Neuroscientists propose that a hyperactive reward system combined with an immature prefrontal cortex contributes to this vulnerability to over consume drugs and natural rewards. Animal and human studies had established that teens brains are at their peak of phasic dopamine production (sensitivity to dopamine) while simultaneously undergoing rapid neuroplastic changes (learning). Dopamine functions as a learning signal can lead to addiction. A few of the many articles, studies, and reviews supporting these assertions:

An interview with famed medical researcher Jay Giedd, (PBS Frontline interview):

What has surprised you about looking at the adolescent brain?

The most surprising thing has been how much the teen brain is changing. By age six, the brain is already 95 percent of its adult size. But the gray matter, or thinking part of the brain, continues to thicken throughout childhood as the brain cells get extra connections, much like a tree growing extra branches, twigs and roots. In the frontal part of the brain, the part of the brain involved in judgment, organization, planning, strategizing -- those very skills that teens get better and better at -- this process of thickening of the gray matter peaks at about age 11 in girls and age 12 in boys, roughly about the same time as puberty.

After that peak, the gray matter thins as the excess connections are eliminated or pruned. So much of our research is focusing on trying to understand what influences or guides the building-up stage when the gray matter is growing extra branches and connections and what guides the thinning or pruning phase when the excess connections are eliminated.

And what do you think this might mean, this exuberant growth of those early adolescent years?

I think the exuberant growth during the pre-puberty years gives the brain enormous potential. The capacity to be skilled in many different areas is building up during those times. What the influences are of parenting or teachers, society, nutrition, bacterial and viral infections -- all these factors -- on this building-up phase, we're just beginning to try to understand. But the pruning-down phase is perhaps even more interesting, because our leading hypothesis for that is the "Use it or lose it" principle. Those cells and connections that are used will survive and flourish. Those cells and connections that are not used will wither and die.

So if a teen is doing music or sports or academics, those are the cells and connections that will be hard-wired. If they're lying on the couch or playing video games or MTV, those are the cells and connections that are going [to] survive.

Right around the time of puberty and on into the adult years is a particularly critical time for the brain sculpting to take place. Much like Michelangelo's David, you start out with a huge block of granite at the peak at the puberty years. Then the art is created by removing pieces of the granite, and that is the way the brain also sculpts itself. Bigger isn't necessarily better, or else the peak in brain function would occur at age 11 or 12. ... The advances come from actually taking away and pruning down of certain connections themselves.

Adolescent cortical development: a critical period of vulnerability for addiction (2007) - Excerpts:

Cortical growth and remodeling continues from birth through youth and adolescence to stable adult levels changing slowly into senescence. There are critical periods of cortical development when specific experiences drive major synaptic rearrangements and learning that only occur during the critical period. Adolescence is defined by characteristic behaviors that include high levels of risk taking, exploration, novelty and sensation seeking, social interaction and play behaviors. In addition, adolescence is the final period of development of the adult during which talents, reasoning and complex adult behaviors mature. This maturation of behaviors corresponds with periods of marked changes in neurogenesis, cortical synaptic remodeling, neurotransmitter receptors and transporters, as well as major changes in hormones. Frontal cortical development is later in adolescence and likely contributes to refinement of reasoning, goal and priority setting, impulse control and evaluating long and short term rewards. Adolescent humans have high levels of binge drinking and experimentation with other drugs. This review presents findings supporting adolescence as a critical period of cortical development important for establishing lifelong adult characteristics that are disrupted by alcohol and drug use.

The teen brain: insights from neuroimaging (2008) - Excerpts:

Few parents of a teenager are surprised to hear that the brain of a 16-year-old is different from the brain of an 8-year-old. Yet to pin down these differences in a rigorous scientific way has been elusive. Magnetic resonance imaging, with the capacity to provide exquisitely accurate quantifications of brain anatomy and physiology without the use of ionizing radiation, has launched a new era of adolescent neuroscience. Longitudinal studies of subjects from ages 3-30 years demonstrate a general pattern of childhood peaks of gray matter followed by adolescent declines, functional and structural increases in connectivity and integrative processing, and a changing balance between limbic/subcortical and frontal lobe functions, extending well into young adulthood.

A time of change: Behavioral and neural correlates of adolescent sensitivity to appetitive and aversive environmental cues (2010) - Excerpts:

Adolescence is a developmental period that entails substantial changes in affective and incentive-seeking behavior relative to both childhood and adulthood, including a heightened propensity to engage in risky behaviors and experience persistent negative and labile mood states. This review discusses the emotional and incentive-driven behavioral changes in adolescents and their associated neural mechanisms, focusing on the dynamic interactions between the amygdala, ventral striatum, and prefrontal cortex. Common behavioral changes during adolescence may be associated with a heightened responsiveness to incentives and emotional cues while the capacity to effectively engage in cognitive and emotion regulation is still relatively immature.

Adolescent Development of the Reward System (2010) - Excerpts:

Investigators have used functional magnetic resonance imaging (fMRI) in conjunction with reward paradigms to test two opposing hypotheses about adolescent developmental changes in the striatum, a region implicated in reward processing. One hypothesis posits that the striatum is relatively hypo-responsive to rewards during adolescence, such that heightened reward-seeking behavior is necessary to achieve the same activation as adults. Another view suggests that during adolescence the striatal reward system is hyper-responsive, which subsequently results in greater reward-seeking. While evidence for both hypotheses has been reported, the field has generally converged on this latter hypothesis based on compelling evidence.

A unique adolescent response to reward prediction errors (2010) - Excerpts:

Previous work has demonstrated that human adolescents may be hypersensitive to rewards; it is unknown which aspect of reward processing this reflects. We separated decision value and prediction error signals and found that neural prediction error signals in the striatum peaked in adolescence, whereas neural decision value signals varied depending upon how value was modeled. This suggests that one contributor to adolescent reward-seeking may be heightened dopaminergic prediction error responsivity.

Teen brains over-process rewards, suggesting root of risky behavior, mental ills (2011) - Excerpts:

The team reports in the Journal of Neuroscience that electrode recordings of adult and adolescent brain-cell activity during the performance of a reward-driven task show that adolescent brains react to rewards with far greater excitement than adult brains. This frenzy of stimulation occurred with varying intensity throughout the study along with a greater degree of disorganization in adolescent brains. The brains of adult rats, on the other hand, processed their prizes with a consistent balance of excitation and inhibition.

The extreme difference in brain activity provides a possible physiological explanation as to why teenagers are more prone than adults to rash behavior, addiction, and mental diseases, said lead researcher Bita Moghaddam, a professor of neuroscience in Pitt's School of Arts and Sciences.

Braking and Accelerating of the Adolescent Brain (2011) - Excerpts:

Adolescence is a developmental period often characterized as a time of impulsive and risky choices leading to increased incidence of unintentional injuries and violence, alcohol and drug abuse, unintended pregnancy and sexually transmitted diseases. Traditional neurobiological and cognitive explanations for such suboptimal choices and actions have failed to account for nonlinear changes in behavior observed during adolescence, relative to childhood and adulthood. This review provides a biologically plausible conceptualization of the mechanisms underlying these nonlinear changes in behavior, as an imbalance between a heightened sensitivity to motivational cues and immature cognitive control. Recent human imaging and animal studies provide a biological basis for this view, suggesting differential development of subcortical limbic systems relative to top-down control systems during adolescence relative to childhood and adulthood.

Dopamine neurons in the ventral tegmental area fire faster in adolescent rats than in adults (2012) - Excerpts:

In conclusion, VTA dopamine neurons fire faster in adolescence, potentially because GABA tone increases as rats reach adulthood. This elevation of firing rate during adolescence is consistent with it representing a vulnerable period for developing drug addiction.

Motivational systems in adolescence: possible implications for age differences in substance abuse and other risk-taking behaviors (2010) - Excerpts:

Adolescence is a developmental phase that is characterized by unique transformations in brain and behavior. Adolescents across a variety of species not only show increases in risk-taking and novelty seeking behaviors, but also demonstrate elevated social interactions with their peers. Brain alterations in regions implicated in mediating motivational and reward-related behaviors likely contribute to expression of these adolescent-typical behaviors. An early maturing or exaggerated reward system, perhaps associated with an augmented responsiveness of the NAc, may lead to an enhanced sensitivity to the positive hedonics of potential rewards during this developmental phase. Additional behavioral evidence suggests that adolescents may conversely exhibit an attenuated sensitivity to aversive properties of stimuli, perhaps in part through developmental alterations in neural components of these same motivational systems, although the neural mechanisms underlying such aversive properties have not been systematically explored in adolescence.

UPDATED SUPPORT:

The following are but a small sampling of the more recent reviews and studies supporting the claims presented on Slide 31.

Nature and nurture teased apart in brain’s reward centre (2012) - Excerpts:

They reached two main conclusions. Firstly, the genetic inheritance and the individual experiences that make each of us unique have an important influence on dopamine function in the striatum. “These are normally experiences that happen a little bit later on in life, in adolescence or early adulthood,” explains Stokes. In contrast, factors in the familial environment, like the experience of sharing a home and growing up together, has little or no influence.

Secondly, the limbic striatum – the part central to reward and motivation – is much more affected by those experiences than the other parts. This suggests, intriguingly, that the pleasure centre and the behaviour it guides are sculpted mostly by life experiences rather than by our genes . This challenges previous assumptions that dopamine function could be straightforwardly inherited, making the causes of schizophrenia and addiction even more mysterious.

Best Memory? You’re Likely to Decide as a Teen (2012) - Excerpts:

Psychologist Dr Steve Janssen said that more memories are accumulated between the ages of 10 and 20 than at any other time of life. He said that while people are likely to have vivid memories of significant events such as marriage, buying a house or the birth of a child from any period of their lives, memories from their second decade of life will be far more numerous and therefore more durable and influential.

Adolescent neurodevelopment (2013) - Excerpts:

Adolescent brain transformations include both progressive and regressive changes that are regionally specific and serve to refine brain functional connectivity. Along with still-maturing inhibitory control systems that can be overcome under emotional circumstances, the adolescent brain is associated with sometimes elevated activation of reward-relevant brain regions, whereas sensitivity to aversive stimuli may be attenuated. At this time, the developmental shift from greater brain plasticity early in life to the relative stability of the mature brain is still tilted more toward plasticity than seen in adulthood, perhaps providing an opportunity for some experience-influenced sculpting of the adolescent brain.

Brain development during adolescence: neuroscientific insights into this developmental period (2013) - Excerpts:

Adolescence is the phase of life between late childhood and adulthood. Typically, adolescents seek diversion, new experiences, and strong emotions, sometimes putting their health at serious risk. New findings in developmental psychology and neuroscience reveal that a fundamental reorganization of the brain takes place in adolescence. In postnatal brain development, the maximum density of gray matter is reached first in the primary sensorimotor cortex, and the prefrontal cortex matures last. Subcortical brain areas, especially the limbic system and the reward system, develop earlier, so that there is an imbalance during adolescence between the more mature subcortical areas and less mature prefrontal areas. This may account for typical adolescent behavior patterns, including risk-taking. The high plasticity of the adolescent brain permits environmental influences to exert particularly strong effects on cortical circuitry. While this makes intellectual and emotional development possible, it also opens the door to potentially harmful influences.

Adolescent cognitive control and reward processing: implications for risk taking and substance use (2013) - Excerpts:

Adolescence is a unique, transitional period of human development. Once hallmark of this period is progressive improvements (relative to children) in cognitive control, core mental abilities enabling the 'top-down', endogenous control over behavior. However, as adolescents transition to more mature (adult) levels of functioning, limitations still exist in the ability to consistently and flexibly exert cognitive control across various contexts into the early twenties. Adolescence is also marked by peaks in sensation, novelty, and reward seeking behaviors thought to stem from normative increases in responsiveness in limbic and paralimbic brain structures, beginning around the onset of puberty. Asynchronous maturation in these systems during the adolescent period likely contributes to immature decision-making, strongly influenced by 'bottom-up' reward processes, and may help explain noted increases in risk taking behavior during adolescence. In this paper, structural and functional maturation in brain systems supporting reward and cognitive control processing are reviewed as a means to better understand risk taking. Particular emphasis is placed on adolescents' experimentation with drugs as a specific example of a risky behavior.

Teen brains really are wired to seek rewards (2014) - Excerpts:

"The current study replicates our previous research that the adolescent brain is more responsive and excitable to rewards compared to adults and to younger children," said Galvan, a neuroscientist at the University of California, Los Angeles, leader of the study detailed online Monday in the journal Proceedings of the National Academy of Sciences.

Neurobiology of Adolescent Substance Use and Addictive Behaviors: Prevention and Treatment Implications (2014) - Excerpts:

Adolescence is a period of dynamic biologic, psychological, and behavioral changes. Adolescence is also associated with an increased risk for substance use and addictive disorders. During adolescence, developmental changes in neural circuitry of reward processing, motivation, cognitive control, and stress may contribute to vulnerability for increased levels of engagement in substance use and nonsubstance addictive behaviors. Current biologic models of adolescent vulnerability for addictions incorporate existing data on allostatic changes in function and structure of the midbrain dopaminergic system, stress-associated neuroplasticity, and maturational imbalances between cognitive control and reward reactivity. Improved understanding of the neurobiology of adolescence and addiction vulnerability has the potential to refine screening, enhance prevention and intervention strategies, and inform public policy.

The developmental mismatch in structural brain maturation during adolescence (2015) - Excerpts:

Regions of the human brain develop at different rates across the first two decades of life, with some maturing before others. It has been hypothesized that a mismatch in the timing of maturation between subcortical regions (involved in affect and reward processing) and prefrontal regions (involved in cognitive control) underlies the increase in risk-taking and sensation-seeking behaviors observed during adolescence. Most support for this 'dual systems' hypothesis relies on cross-sectional data, and it is not known whether this pattern is present at an individual level…... Taken together, it appears that the developmental mismatch in structural brain maturation is present in neurotypically developing individuals.

Longitudinal changes in adolescent risk-taking: a comprehensive study of neural responses to rewards, pubertal development, and risk-taking behavior (2015) - Excerpts:

Prior studies have highlighted adolescence as a period of increased risk-taking, which is postulated to result from an overactive reward system in the brain….

The longitudinal analyses confirmed the quadratic age pattern for nucleus accumbens activity to rewards (peaking in adolescence), and the same quadratic pattern was found for laboratory risk-taking (BART). Nucleus accumbens activity change was further related to change in testosterone and self-reported reward-sensitivity (BAS Drive). Thus, this longitudinal analysis provides new insight in risk-taking and reward sensitivity in adolescence: (1) confirming an adolescent peak in nucleus accumbens activity, and (2) underlining a critical role for pubertal hormones and individual differences in risk-taking tendency.

Adolescent neuroscience of addiction: A new era (2015) – Excerpts:

Adolescence has long been recognized as a time of dramatic changes in body and behavior. More recently it is being recognized as a time of dramatic changes in brain as well. Advances in neuroimaging technologies have made knowledge of the anatomy and physiology of the developing brain increasingly accessible.

Several large scale initiatives using magnetic resonance imaging (MRI) to characterize adolescent brain maturation in health and illness, often integrated with genetics and progressively sophisticated behavioral and environmental measures, are beginning to yield insights into why adolescence is a time of both opportunity and of vulnerability.

During adolescence the brain does not mature by becoming larger and larger. It matures by becoming more interconnected and more specialized.

The increasing interconnectedness, or communication amongst disparate brain regions comprising an elaborately embedded hierarchy of neural circuits, is demonstrated across multiple modalities and levels of investigation. Studies of long term potentiation indicate the formation of stronger synaptic connections during adolescence. Greater coherence of electrical activity (the degree to which activity in one area can be predicted from activity in another) is shown by studies using EEG. Similarly, fMRI studies assessing blood oxygenation also show a general trend toward greater co-activation amongst spatially distinct regions. And structural MRI studies find increases in white matter volume during adolescence reflecting myelination and concomitant increases in the speed of neural communication.

The increasing specialization of the adolescent brain is indirectly expressed as decreases in gray matter volumes during the second decade, although much work remains to be done to understand the molecular and microscopic processes underlying the observation. Increases in myelination, which may flip the designation of an MRI voxel at the inner border of the cortex from gray to white, account for some of the “reduction” in gray matter volume, but converging evidence from post mortem studies and regionally specific mismatches between developmental trajectories of gray and white matter volumes suggest other processes are contributing as well. The extent to which “pruning” of synapses contributes to the gray matter volume reductions is unknown. This is an important question to resolve in order to shed light on the over simplified notion that specialization is subserved by the phenomenon of fewer but faster/firmer connections. Understanding the mechanisms is fundamental to guiding interventions and refining hypotheses for future investigations.

Perhaps the most striking change of adolescent brain development is the degree of change itself. A key feature of adolescent brain development is plasticity, the ability of the brain to change in response to demands of the environment. Some degree of plasticity is maintained throughout life but in general there is a developmental gradient of decreasing plasticity as myelin releases proteins such as Nogo-A, MAG and OMgp that inhibit axon sprouting and the creation of new synapses (Fields, 2008). However, humans have a uniquely long period of high plasticity allowing us to be remarkably adaptable to a wide range of conditions. Prolonged plasticity may be related to prolonged dependency on caregivers as across species. A longer period of dependence is associated with more complex social and food securing behavior. By “keeping options open” in terms of brain specialization, humans can assess the demands of their particular environmental and develop the skills to survive. Humans can thrive everywhere from the frigid North and South poles to the balmy islands on the equator. We have adapted to cultural changes as well. Ten thousand years ago, a brief amount of time in evolutionary terms, we spent much of our time securing food and shelter. Now most humans can secure shelter and calories with far less time and effort, which via epigenetic or other factors may be related to earlier puberty and greater size. Instead of securing food many of us now spend the majority of our time interacting with words or symbols. This is a notable adaptation given that reading is only 5000 years old and did not exist for much of human history.

Further support for the advantage of prolonged plasticity comes from the observation that our last increase in brain size about 500,000 years ago correlates not with the harshness of climate but the degree of climate change. This is in contrast to Neanderthals, our close genetic relatives. Maturational rates can be assessed from fossilized teeth in much the same way that tree rings can be used to discern growth rates for trees. Evidence from fossilized Neanderthal teeth indicate that they had a much more rapid maturation (Ramirez Rozzi and Bermudez De Castro, 2004). Although their brains were about 10% larger and they were able to survive in harsh environments, their tool use did not change over 100,000 years. They lacked the adolescent plasticity and adaptability of humans.

Adolescent brain plasticity has served our species well, however it comes at a price. It creates vulnerabilities as well as opportunities. Over half of all mental illness emerges during adolescence. One in five adolescents has a mental illness that will persist into adulthood. It is the peak time for the emergence of anxiety disorders, bipolar disorder, depression, eating disorders, and psychosis. It is also the most common time for the onset of substance abuse.

Adolescence is increasingly being recognized as a distinct developmental stage with distinct biology rather than just as an intermediate stage between childhood and adulthood.

Neurobiology of Adolescent Substance Use Disorder (2016) - Excerpts:

There are many facets of the neurobiology of substance use that are distinct in adolescence as compared with adulthood. The adolescent brain is subject to intense subcortical reward processes, but is left with an immature prefrontal control system that is often unable to resist the pull of potentially exciting activities like substance use, even when fully aware of the dangers involved. Peer influences serve only to magnify these effects and foster more sensation-seeking, risky behavior. The unique aspects of neurobiology should be taken into consideration when designing prevention programs and clinical interventions for adolescent substance use disorders.


SLIDE 32

By adulthood, teens strengthen heavily used circuits and prune back unused ones. So – by age 22 or so – a guy’s sexual tastes can be like deep ruts in his brain. This can cause panic - if he has escalated to extreme porn, or porn that no longer matches his sexual orientation. Fortunately, brains are plastic, and tastes can revert after a guy quits porn.

ORIGINAL SUPPORT:

This slide contains two claims:

  1. Adolescents strengthen heavily used neural connections (synapses) and eliminate (or silence) billions of lesser used synapses.
  2. Adolescent porn users can escalate to extreme porn, or porn that no longer matches their original sexual identity (however, this doesn't mean that porn use can change one's fundamental sexual orientation)

The first claim - that adolescents strengthen heavily used neural connections (synapses) and eliminate (or silence) billions of lesser used synapses - is well supported in human and animal studies. See previous slide for support.

Support for claim #2: that some young porn users experience habituation and escalate to "extreme" genres or genres that do not match original sexual preferences (however, this doesn't mean that porn use can change fundamental sexual orientation)

First, a bit of context for claim #2. In 2011, no study had directly asked porn users about escalation of porn use or morphing porn tastes (or their reversal). So claims that internet porn users never escalate and preferred genres never changed, were without empirical or clinical support. The Great Porn Experiment claims that porn users preferred genres can change over time, leading many to watch, and be sexually aroused by, porn that's inconsistence with their original sexual template. Researchers often employ "sexual script theory" to understand how pornography shapes a young man's sexual tastes (for more see: Pornography and the Male Sexual Script: An Analysis of Consumption and Sexual Relations, 2014).

Support for the claim that porn can shape sexual templates came from self reports of porn-induced "sexual tastes" reversing after men eliminated porn. The following pages contain many such stories.

The claim was also supported by what Norman Doidge MD wrote about this in his 2007 book The Brain That Changes Itself:

The current porn epidemic gives a graphic demonstration that sexual tastes can be acquired. Pornography, delivered by high-speed Internet connections, satisfies every one of the prerequisites for neuroplastic change.... When pornographers boast that they are pushing the envelope by introducing new, harder themes, what they don't say is that they must, because their customers are building up a tolerance to the content. The back pages of men's risque magazines and Internet porn sites are filled with ads for Viagra-type drugs—medicine developed for older men with erectile problems related to aging and blocked blood vessels in the penis. Today young men who surf porn are tremendously fearful of impotence, or “erectile dysfunction” as it is euphemistically called. The misleading term implies that these men have a problem in their penises, but the problem is in their heads, in their sexual brain maps. The penis works fine when they use pornography. It rarely occurs to them that there may be a relationship between the pornography they are consuming and their impotence.

In 2011, a few studies supported the claim that porn users habituate to current porn genres and escalated to more extreme genres:

1) Shifting Preferences In Pornography Consumption (1986) - Six weeks of exposure to nonviolent pornography resulted in subjects having little interest in vanilla porn, electing to almost exclusively watch "uncommon pornography" (bondage, sadomasochism, bestiality). An excerpt:

Male and female students and nonstudents were exposed to one hour of common, nonviolent pornography or to sexually and aggressively innocuous materials in each of six consecutive weeks. Two weeks after this treatment, they were provided with an opportunity to watch videotapes in a private situation. G-rated, R-rated, and X-rated programs were available. Subjects with considerable prior exposure to common, nonviolent pornography showed little interest in common, nonviolent pornography, electing to watch uncommon pornography (bondage, sadomasochism, bestiality) instead. Male nonstudents with prior exposure to common, nonviolent pornography consumed uncommon pornography almost exclusively. Male students exhibited the same pattern, although somewhat less extreme. This consumption preference was also in evidence in females, but was far less pronounced, especially among female students.

2) The Dual Control Model - The Role Of Sexual Inhibition & Excitation In Sexual Arousal And Behavior (2007) - In an experiment employing video porn, 50% of the young men couldn't become aroused or achieve erections with porn (average age was 29). The shocked researchers discovered that the men's erectile dysfunction was,

related to high levels of exposure to and experience with sexually explicit materials.

The men experiencing erectile dysfunction had spent a considerable amount of time in bars and bathhouses where porn was "omnipresent," and "continuously playing." The researchers stated:

Conversations with the subjects reinforced our idea that in some of them a high exposure to erotica seemed to have resulted in a lower responsivity to "vanilla sex" erotica and an increased need for novelty and variation, in some cases combined with a need for very specific types of stimuli in order to get aroused.

The following excerpt is taken from the book "The Psychophysiology of Sex, Chapter: The Dual-Control Model: The role of sexual inhibition & excitation in sexual arousal and behavior." Publisher: Indiana University Press, Editors: Erick Janssen, pp.197-222 (link to the chapter):

As part of our research on sexual risk taking, presented earlier in this paper, we invited our questionnaire and interview subjects to also participate in a psychophysiological study (Janssen, Goodrich, Petrocelli, & Bancroft, 2006). In view of the complexity of the preliminary findings of the shock-threat study, we instead decided to use the design of our first laboratory study on the dual control model (Janssen et al., 2002b).

When we applied this design (with the two types of sexual film, distraction and performance demand) to this new sample, however, we encountered another unanticipated, yet intriguing, phenomenon. Twelve men, or almost 50% of the first 25 subjects (mean age = 29 years), did not respond to the sexual stimuli (i.e., penile rigidity of less than 5% to the noncoercive film clips; 8 men had 0% rigidity). This is, to our knowledge, one of the few psychophysiological studies in which men participated who were recruited from the community--in our case, from bath houses, STD clinics, bars, and so on.

In some of these venues, sexual stimuli (including video screens) are omnipresent, and this, in combination with comments from participants about the lack of more interesting, specialized ("niche"), or more extreme or "kinky" stimuli, made us consider the possibility that the unusually high rate of nonresponders could be related to high levels of exposure to and experience with sexually explicit materials. Conversations with the subjects reinforced our idea that in some of them a high exposure to erotica seemed to have resulted in a lower responsivity to "vanilla sex" erotica and an increased need for novelty and variation, in some cases combined with a need for very specific types of stimuli in order to get aroused.

We redesigned the study and decided to eliminate the distraction and performance demand manipulations and to include newer, more varied clips, as well as some longer film clips. Also, instead of presenting subjects with a set of preselected ("researcher-selected") videos only, we let them choose two clips themselves from a set of 10, of which 10-second previews were shown and that included a wider range of sexual behaviors (e.g., group sex, interracial sex, S & M, etc.). We recruited an additional 51 subjects and found that with the improved design still 20 men, or approximately 25%, did not respond well to the sexual video clips (penile rigidity of less than 10% in response to the long self-selected film).

We conducted a logistic regression analysis to determine if high responders could be differentiated from low responders using age, sexual orientation, SES, SIS1, SIS2, experience with erotic videos, self-reported erectile difficulties, and sexual risk taking as predictor variables. The regression model significantly discriminated between the two groups (÷2(8) = 22.26, p < .01; see Table 2), explaining 39% of the variance. In total 78% of the participants were correctly classified (z = 4.61, p < .001), with hit rates of 82% for high and 59% for low responders (ps < .01). The results indicate that a participant was more likely to be classified as a high responder as his age decreased and his SES and sexual risk taking scores increased. Homosexual participants were more likely to be classified as low responders than heterosexual participants. Finally, the analyses suggested that as the number of erotic films seen within the past year increased a participant was more likely to be classified as a low responder.

By 2011, numerous studies had suggested that porn use influences both sexual attitudes and sexual behaviors. Similarly, a handful of studies had examined whether porn shaped the sexual templates of users ("sexual script theory"). The following studies propose that porn did just that: 

Does pornography influence young women's sexual behavior? (2003) - An excerpt:

Young women (n = 1,000), visiting a family planning clinic in Stockholm, Sweden, answered a questionnaire about their sexual behavior and if they had seen pornography. Four out of five had consumed pornography, and one-third of these believed that pornography had impacted their sexual behavior. As many as 47% had experienced anal intercourse, which was significantly more common among older women (51%) than among teenagers (31%). The majority valued anal intercourse as a negative experience.

Sexual behaviour among young men in Sweden and the impact of pornography (2004) - An excerpt:

The purpose was to investigate the sexual behaviour among young men (n = 300), visiting a genitourinary clinic in Sweden, focusing on the impact of pornography. Almost all, 98%  claimed to be heterosexual. All, 99% had consumed pornography and 53% felt that pornography impacted their sexual behaviour.

Associations between pornography consumption and sexual practices among adolescents in Sweden (2005) - An excerpt:

More men (98%) than women (72%) had ever consumed pornography.... More male high consumers than low consumers or women got sexually aroused by, fantasized about, or tried to perform acts seen in a pornographic film.

Associations between young adults' use of sexually explicit materials and their sexual preferences, behaviors, and satisfaction (2011) - An excerpt:

This study examined how levels of sexually explicit material (SEM) use during adolescence and young adulthood were associated with sexual preferences, sexual behaviors, and sexual and relationship satisfaction.... The frequency of SEM use and number of SEM types viewed were both associated with higher sexual preferences for the types of sexual practices typically presented in SEM.

UPDATED SUPPORT:

Updated support for the claim that some porn users can experience habituation or escalate to "extreme" genres or genres that do not match original sexual preferences (but not alter fundamental orientation).

First we start with 4 studies that directly asked porn users about escalation into new or more extreme genres of porn. All support the claims put forth in Slide 32:

1) This was the first study to ask internet porn users directly about escalation: "Online sexual activities: An exploratory study of problematic and non-problematic usage patterns in a sample of men" (2016). The study reports escalation, as 49% of the men reported viewing porn that was not previously interesting to them or that they once considered disgusting. An excerpt:

Forty-nine percent mentioned at least sometimes searching for sexual content or being involved in OSAs that were not previously interesting to them or that they considered disgusting.

This Belgian study also found problematic Internet porn use was associated with reduced erectile function and reduced overall sexual satisfaction. Yet problematic porn users experienced greater cravings. Interestingly, 20.3% of participants said that one motive for their porn use was "to maintain arousal with my partner." (OSA's = online sexual activity, which was porn for 99% of subjects) An excerpt:

This study is the first to directly investigate the relationships between sexual dysfunctions and problematic involvement in OSAs. Results indicated that higher sexual desire, lower overall sexual satisfaction, and lower erectile function were associated with problematic OSAs (online sexual activities). These results can be linked to those of previous studies reporting a high level of arousability in association with sexual addiction symptoms (Bancroft & Vukadinovic, 2004; Laier et al., 2013; Muise et al., 2013).

2) A 2017 study asked porn users directly about tolerance and withdrawal symptoms: The Development of the Problematic Pornography Consumption Scale (PPCS) (2017) - This paper developed and tested a problematic porn use questionnaire that was modeled after substance addiction questionnaires. Unlike previous porn addiction tests, this 18-item questionnaire assessed tolerance and escalation with the following 3 questions:

  • I gradually watched more “extreme” porn, because the porn I watched before was less satisfying.
  • I felt that I needed more and more porn in order to satisfy my needs.
  • I felt that I had to watch more and more porn for satisfaction.

Each question was scored from one to seven on a Likert scale: 1- Never, 2- Rarely, 3- Occasionally, 4- Sometimes, 5- Often, 6- Very Often, 7- All the Time. Put simply, some porn users reported both escalation and tolerance.

3) Out-of-control use of the internet for sexual purposes as behavioural addiction? An upcoming study (presented at the 4th International Conference on Behavioral Addictions, February 20–22, 2017) also directly asked about tolerance and withdrawal. It found both in "pornography addicts". 

There is an ongoing debate whether excessive sexual behaviour should be understood as a form of behavioural addiction (Karila, Wéry, Weistein et al., 2014). The present qualitative study aimed at analysing the extent to which out-of-control use of the internet for sexual purposes (OUISP) may be framed by the concept of behavioural addiction among those individuals who were in treatment due to their OUISP.

We conducted in-depth interviews with 21 participants aged 22–54 years (Mage = 34.24 years). Using a thematic analysis, the clinical symptoms of OUISP were analysed with the criteria of behavioural addiction, with the special focus on tolerance and withdrawal symptoms (Griffiths, 2001).

The dominant problematic behaviour was out-of-control online pornography use (OOPU). Building up tolerance to OOPU manifested itself as an increasing amount of time spent on pornographic websites as well as searching for new and more sexually explicit stimuli within the non-deviant spectrum. Withdrawal symptoms manifested themselves on a psychosomatic level and took the form of searching for alternative sexual objects. Fifteen participants fulfilled all of the addiction criteria.

Three papers suggest that porn users with no pedophilic interests can escalate to viewing child pornography.

4) In addition, this 2016 study casts doubt on that assumption that sexual tastes are stable with respect to today's (streaming) internet pornography: Sexually Explicit Media Use by Sexual Identity: A Comparative Analysis of Gay, Bisexual, and Heterosexual Men in the United States. Excerpt from this study:

The findings also indicated that many men viewed sexually explicit material (SEM) content inconsistent with their stated sexual identity. It was not uncommon for heterosexual-identified men to report viewing SEM containing male same-sex behavior (20.7%) and for gay-identified men to report viewing heterosexual behavior in SEM (55.0%)

The above four studies fully support Slide 32 while falsifying the often repeated claim that today's porn users eventually "discover their true sexuality" by surfing tube sites, and then stick to only one genre of porn for the rest of time. Employing various methodologies and approaches, a diverse group of studies have reported habituation to "regular porn" along with escalation into more extreme and unusual genres:

1) Brain Structure and Functional Connectivity Associated With Pornography Consumption: The Brain on Porn (Kuhn & Gallinat, 2014) - This Max Planck Institute fMRI study found less grey matter in the reward system (dorsal striatum) correlating with the amount of porn consumed. It also found that more porn use correlated with less reward circuit activation while briefly viewing sexual photos. Researchers believe their findings indicated desensitization, and possibly tolerance, which is the need for greater stimulation to achieve the same level of arousal. Lead author Simone Kühn said the following about her study:

That could mean that regular consumption of pornography more or less wears out your reward system. We assume that subjects with a high porn consumption need increasing stimulation to receive the same amount of reward. That would fit perfectly the hypothesis that their reward systems need growing stimulation.

2) Novelty, conditioning and attentional bias to sexual rewards (2015). A Cambridge University fMRI study reported greater habituation to sexual stimuli in compulsive porn users. An excerpt from the related press release:

They found that when the sex addicts viewed the same sexual image repeatedly, compared to the healthy volunteers they experienced a greater decrease of activity in the region of the brain known as the dorsal anterior cingulate cortex, known to be involved in anticipating rewards and responding to new events. This is consistent with 'habituation', where the addict finds the same stimulus less and less rewarding – for example, a coffee drinker may get a caffeine 'buzz' from their first cup, but over time the more they drink coffee, the smaller the buzz becomes.

This same habituation effect occurs in healthy males who are repeatedly shown the same porn video. But when they then view a new video, the level of interest and arousal goes back to the original level. This implies that, to prevent habituation, the sex addict would need to seek out a constant supply of new images. In other words, habituation could drive the search for novel images.

"Our findings are particularly relevant in the context of online pornography," adds Dr Voon. "It's not clear what triggers sex addiction in the first place and it is likely that some people are more pre-disposed to the addiction than others, but the seemingly endless supply of novel sexual images available online helps feed their addiction, making it more and more difficult to escape."

3) Modulation of late positive potentials by sexual images in problem users and controls inconsistent with "porn addiction (Prause et al., 2015.) Compared to controls "individuals experiencing problems regulating their porn viewing" had lower brain responses to one-second exposure to photos of vanilla porn. Lower EEG readings mean that subjects are paying less attention to the pictures. Put simply, frequent porn users were desensitized to static images of vanilla porn. They were bored (habituated or desensitized). Six peer-reviewed papers agree with this extensive critique that this study found desensitization/habituation in frequent porn users: 1, 2, 3, 4, 5, 6.

4) Conscious and Non-Conscious Measures of Emotion: Do They Vary with Frequency of Pornography Use? (2017) – The study assessed porn users' responses (EEG readings & Startle Response) to various emotion-inducing images - including erotica. The authors believe two findings indicate habituation in the more frequent porn users. Excerpts:

4.1. Explicit Ratings

Interestingly, the high porn use group rated the erotic images as more unpleasant than the medium use group. The authors suggest this may be due to the relatively “soft-core” nature of the “erotic” images contained in the IAPS database not providing the level of stimulation that they may usually seek out, as it has been shown by Harper and Hodgins [58] that with frequent viewing of pornographic material, many individuals often escalate into viewing more intense material to maintain the same level of physiological arousal. The “pleasant” emotion category saw valence ratings by all three groups to be relatively similar with the high use group rating the images as slightly more unpleasant on average than the other groups. This may again be due to the “pleasant” images presented not being stimulating enough for the individuals in the high use group. Studies have consistently shown a physiological downregulation in processing of appetitive content due to habituation effects in individuals who frequently seek out pornographic material [3, 7, 8]. It is the authors’ contention that this effect may account for the results observed.

4.3. Startle Reflex Modulation (SRM)

The relative higher amplitude startle effect seen in the low and medium porn use groups may be explained by those in the group intentionally avoiding the use of pornography, as they may find it to be relatively more unpleasant. Alternatively, the results obtained also may be due to a habituation effect, whereby individuals in these groups do watch more pornography than they explicitly stated—possibly due to reasons of embarrassment among others, as habituation effects have been shown to increase startle eye blink responses [41, 42].

5) Exploring the Relationship between Sexual Compulsivity and Attentional Bias to Sex-Related Words in a Cohort of Sexually Active Individuals (2017) - This study replicates the findings of this 2014 Cambridge University study that compared the attentional bias of porn addicts to healthy controls. In addition, the study correlated the "years of sexual activity" with 1) the sex addiction scores and also 2) the results of the attentional bias task. Among those scoring high on sexual addiction, fewer years of sexual experience were related to greater attentional bias. So higher sexual compulsivity scores + fewer years of sexual experience = greater signs of addiction (greater attentional bias, or interference). But attentional bias declines sharply in the compulsive users, and disappears at the highest number of years of sexual experience. The authors concluded that this result could indicate that more years of "compulsive sexual activity" lead to greater habituation or a general numbing of the pleasure response (desensitization). An excerpt from the conclusion:

One possible explanation for these results is that as a sexually compulsive individual engages in more compulsive behaviour, an associated arousal template develops [36–38] and that over time, more extreme behaviour is required for the same level of arousal to be realised. It is further argued that as an individual engages in more compulsive behaviour, neuropathways become desensitized to more ‘normalised’ sexual stimuli or images and individuals turn to more ‘extreme’ stimuli to realise the arousal desired. This is in accordance with work showing that ‘healthy’ males become habituated to explicit stimuli over time and that this habituation is characterised by decreased arousal and appetitive responses [39]. This suggests that more compulsive, sexually active participants have become ‘numb’ or more indifferent to the ‘normalised’ sex-related words used in the present study and as such display decreased attentional bias, while those with increased compulsivity and less experience still showed interference because the stimuli reflect more sensitised cognition.

6) Neural Substrates of Sexual Desire in Individuals with Problematic Hypersexual Behavior (2015) - This Korean fMRI study replicates several other neurological studies on porn users: it reported cue-induced brain activation patterns and alterations in the prefrontal cortex that mirrored those occurring in drug addicts. In line with addiction model, sex addicts had greater cue-reactivity for sexual images, yet inhibited brain activation to other types of normally salient stimuli. Less neural response to normal everyday rewards is the primary indicator of desensitization.

The next two studies found that deviant (i.e., bestiality or minor) pornography users had a significantly younger onset of adult pornography use. Put simply, both studies link earlier onset of adult porn use with escalation to more extreme material.

6) Does deviant pornography use follow a Guttman-like progression?" (2013). An excerpt:

Results suggested deviant pornography use followed a Guttman-like progression in that individuals with a younger “age of onset” for adult pornography use were more likely to engage in deviant pornography (bestiality or child) compared to those with a later “age of onset”.

7) "Deviant Pornography Use: The Role of Early-Onset Adult Pornography Use and Individual Differences" (2016). An excerpt:

Results indicated that adult + deviant pornography users scored significantly higher on openness to experience and reported a significantly younger age of onset for adult pornography use compared to adult-only pornography users.

8) Exploring the effect of sexually explicit material on the sexual beliefs, understanding and practices of young men: A qualitative survey. A qualitative study reports escalation to extreme material. An excerpt:

Findings suggest that the key themes are: increased levels of availability of SEM, including an escalation in extreme content (Everywhere You Look) which are seen by young men in this study as having negative effects on sexual attitudes and behaviours (That's Not Good). Family or sex education may offer some ‘protection’ (Buffers) to the norms young people see in SEM. Data suggests confused views (Real verses Fantasy) around adolescents’ expectations of a healthy sex life (Healthy Sex Life) and appropriate beliefs and behaviours (Knowing Right from Wrong). A potential causal pathway is described and areas of intervention highlighted.

10) Unusual masturbatory practice as an etiological factor in the diagnosis and treatment of sexual dysfunction in young men (2014). One of the 4 case studies in this paper reports on a man with porn-induced sexual problems (low libido, multiple porn fetishes, anorgasmia). The sexual intervention called for a 6-week abstinence from porn and masturbation. After 8 months the man reported increased sexual desire, successful sex and orgasm, and enjoying “good sexual practices." Excerpts from the paper documenting the patient's habituation and escalation into what he described as more extreme porn genres:

When asked about masturbatory practices, he reported that in the past he had been masturbating vigorously and rapidly while watching pornography since adolescence. The pornography originally consisted mainly of zoophilia, and bondage, domination, sadism, and masochism, but he eventually got habituated to these materials and needed more hardcore pornography scenes, including transgender sex, orgies, and violent sex. He used to buy illegal pornographic movies on violent sex acts and rape and visualized those scenes in his imagination to function sexually with women. He gradually lost his desire and his ability to fantasize and decreased his masturbation frequency.

An excerpt from the paper documents the patient's recovery from porn-induced sexual problems and fetishes:

In conjunction with weekly sessions with a sex therapist, the patient was instructed to avoid any exposure to sexually explicit material, including videos, newspapers, books, and internet pornography. After 8 months, the patient reported experiencing successful orgasm and ejaculation. He renewed his relationship with that woman, and they gradually succeeded in enjoying good sexual practices.

11)  Is Internet Pornography Causing Sexual Dysfunctions? A Review with Clinical Reports (2016) is an extensive review of the literature related to porn-induced sexual problems. Co-authored by US Navy doctors, the review provides the latest data revealing a tremendous rise in youthful sexual problems. It also reviews the neurological studies related to porn addiction and sexual conditioning via Internet porn. The doctors include 3 clinical reports of servicemen who developed porn-induced sexual dysfunctions. Two of the three servicemen healed their sexual dysfunctions by eliminating porn use while the third man experienced little improvement as he was unable to abstain from porn use. Two of the three servicemen reported habituation to current porn and escalation of porn use. The first serviceman describes his habituation to "soft porn" followed by escalation into more graphic and fetish porn: 

A 20-year old active duty enlisted Caucasian serviceman presented with difficulties achieving orgasm during intercourse for the previous six months. It first happened while he was deployed overseas. He was masturbating for about an hour without an orgasm, and his penis went flaccid. His difficulties maintaining erection and achieving orgasm continued throughout his deployment. Since his return, he had not been able to ejaculate during intercourse with his fiancée. He could achieve an erection but could not orgasm, and after 10–15 min he would lose his erection, which was not the case prior to his having ED issues.

Patient endorsed masturbating frequently for “years”, and once or twice almost daily for the past couple of years. He endorsed viewing Internet pornography for stimulation. Since he gained access to high-speed Internet, he relied solely on Internet pornography. Initially, “soft porn”, where the content does not necessarily involve actual intercourse, “did the trick”. However, gradually he needed more graphic or fetish material to orgasm. He reported opening multiple videos simultaneously and watching the most stimulating parts.

The second serviceman describes increased porn use and escalation into more graphic porn. Soon thereafter sex with his wife “not as stimulating as before":

A 40-year old African American enlisted serviceman with 17 years of continuous active duty presented with difficulty achieving erections for the previous three months. He reported that when he attempted to have sexual intercourse with his wife, he had difficulty achieving an erection and difficulty maintaining it long enough to orgasm. Ever since their youngest child left for college, six months earlier, he had found himself masturbating more often due to increased privacy. He formerly masturbated every other week on average, but that increased to two to three times per week. He had always used Internet pornography, but the more often he used it, the longer it took to orgasm with his usual material. This led to him using more graphic material. Soon thereafter, sex with his wife was “not as stimulating” as before and at times he found his wife “not as attractive”. He denied ever having these issues earlier in the seven years of their marriage. He was having marital issues because his wife suspected he was having an affair, which he adamantly denied.

13) The Relationship between Frequent Pornography Consumption, Behaviors, and Sexual Preoccupancy among Male Adolescents in Sweden (2017) - Porn use in 18-year old males was universal, and frequent porn users preferred hard-core porn. Does this indicate escalation of porn use?

Among frequent users, the most common type of pornography consumed was hard core pornography (71%) followed by lesbian pornography (64%), while soft core pornography was the most commonly selected genre for average (73%) and infrequent users (36%). There was also a difference between the groups in the proportion who watched hard core pornography (71%, 48%, 10%) and violent pornography (14%, 9%, 0%).

The authors suggest that frequent porn may ultimately lead to a preference for hard-core or violent pornography:

It is also noteworthy that a statistically significant relationship was found between fantasizing about pornography several times a week and watching hard core pornography. Since verbal and physical sexual aggression is so commonplace in pornography, what most adolescents considered hard core pornography could likely be defined as violent pornography. If this is the case, and in light of the suggested cyclical nature of sexual preoccupancy in Peter and Valkenburg, it may be that rather than ‘purging’ individuals of their fantasies and inclinations of sexual aggression, watching hard core pornography perpetuates them, thereby increasing the likelihood of manifested sexual aggression.

14) How difficult is it to treat delayed ejaculation within a short-term psychosexual model? A case study comparison (2017) - This is a report on two "composite cases" illustrating the causes and treatments for delayed ejaculation (anorgasmia). "Patient B" represented several young men treated by the therapist. Interestingly, the paper states that Patient B's "porn use had escalated into harder material", "as is often the case". The paper says that porn-related delayed ejaculation is not uncommon, and on the rise. The author calls for more research on porn's effects of sexual functioning. Patient B's delayed ejaculation was healed after 10 weeks of no porn. Excerpts related to escalation:

The cases are composite cases taken from my work within the National Health Service in Croydon University Hospital, London. With the latter case (Patient B), it is important to note that the presentation reflects a number of young males who have been referred by their GPs with a similar diagnosis. Patient B is a 19-year-old who presented because he was unable to ejaculate via penetration. When he was 13, he was regularly accessing pornography sites either on his own through internet searches or via links that his friends sent him. He began masturbating every night while searching his phone for image…If he did not masturbate he was unable to sleep. The pornography he was using had escalated, as is often the case (see Hudson-Allez, 2010), into harder material (nothing illegal)…

Patient B was exposed to sexual imagery via pornography from the age of 12 and the pornography he was using had escalated to bondage and dominance by the age of 15.

We agreed that he would no longer use pornography to masturbate. This meant leaving his phone in a different room at night. We agreed that he would masturbate in a different way….The article calls for research into pornography usage and its effect on masturbation and genital desensitisation.

By 2017, several more studies had employed "Sexual Script Theory" to analyze porn's effects on the user. An excerpt about sexual script theory from a 2017 peer-reviewed review of the literature, Pornography, Pleasure, and Sexuality: Towards a Hedonic Reinforcement Model of Sexually Explicit Internet Media Use,

Sexual Script Theory

Another possible implication for the present work can be seen in its integration with media effects extensions of sexual script theory. Sexual script theory posits that human sexuality is guided by social influences that create scripts for determining sexual desires, fantasies, and practices (Gagnon & Simon, 2005; Simon & Gagnon, 1986). People observe, learn, and modify the scripts in their environment, using them as cognitive guides for how to pursue and engage with real-life sexual partners. In regards to sexual media generally and pornography specifically, Wright has integrated the concept of sexual scripting with research and theory from communication, media effects, observational learning, and information processing into a sexual script Acquisition, Activation, Application model (3AM) of sexual media socialization (Wright, 2011, 2014; Wright & Bae, 2016; Wright, Malamuth, & Donnerstein, 2012; Wright & Donnerstein, 2014). Within the 3AM, acquisition refers to the processes by which a consumer of sexual media develops new or novel sexual scripts based on the sexual philosophies espoused and behaviors exhibited by media models. For example, an IP consumer might develop a particular fetish or behavioral preference that had not existed for them prior to IPU due to the statements and actions of actors in pornography. Script activation refers to the processes by which sexual media may trigger, or prime, existing sexual scripts. An IP consumer may have learned scripts for both relational, other-oriented sex and casual, self-interested sex, for example, but their IPU keeps the latter script more centrally activated in memory. Finally, application refers to the processes by which a sexual script that has been acquired and activated is called on to guide a particular judgment, attitude, or behavior.

Numerous moderating variables are specified at each stage of the model. Whether observed sexual scripts are actually acquired, activated, and applied depends on a number of content, audience, and situational factors. That more recent and frequent exposures increase the probability of effects, however, are key model tenets. Thus, the present model’s thesis that regular IPU is both motivated by and reinforcing of hedonic sexual motivations is highly consistent with the 3AM.

Studies guided by the 3AM in the context of IPU (e.g., Braithwaite, Coulson, et al., 2015; Braithwaite, Givens, et al., 2015; Donevan & Mattebo, 2017; Lim et al., 2017; Sun et al., 2015; Tomaszewska & Krahe, 2016; Wright & Randall, 2012; Wright & Arroyo, 2013; Wright, 2013b; Wright, Tokunaga, & Kraus, 2016) have found evidence supporting its conclusions, with many such findings consistent with the position that IPU is associated with a more hedonic sexuality. There clearly seems to be an influence of IP on the acquisition or development of specific sexual scripts, the activation of already existing scripts, and the application of those scripts. Additionally, as has been repeatedly discussed in script-theory literature, the sexual scripts available in IP tend to be hedonically self-focused in nature, particularly for men (Brown & L’Engle, 2009; Stulhofer et al., 2010; Sun et al., 2013). Therefore, the present model may be seen as a specific application of the 3AM, in that the current model directly speaks to the role of IP in acquiring, activating, and applying hedonic sexual scripts.

In addition to the above habituation and escalation studies, several additional studies have examined how porn use shapes the sexuality of users ("sexual script theory"):

1) Anal heterosex among young people and implications for health promotion: a qualitative study in the UK (2014) – Excerpt:

Anal heterosex often appeared to be painful, risky and coercive, particularly for women. Interviewees frequently cited pornography as the 'explanation' for anal sex.

2) Pornography and the Male Sexual Script: An Analysis of Consumption and Sexual Relations (2014) – Excerpt:

The growing presence of pornography in men’s sexual socialization raises questions about the potential impact of pornography on dyadic sexual encounters; how might pornography use shape heterosexual men’s sexual behaviors, attitudes, and expectations during sexual encounters with women? Our research indicates that men who view high rates of pornography are more likely to rely on pornography to become and remain sexually excited and, when engaged in dyadic sexual behaviors, are more likely to integrate pornography in sexual activities. In addition, men with high rates of pornography use expressed diminished enjoyment in the enactment of sexually intimate behaviors compared to men with lower rates of pornography use. On the other hand, pornography use was not significantly associated with sexual insecurities.

3) Human Sexual Development is Subject to Critical Period Learning: Implications for Sexual Addiction, Sexual Therapy, and for Child Rearing (2014) – Excerpt:

A novel orientation-neutral Hypersexuality and Risky Sexual Behaviors Scale provided evidence consistent with the idea that both sexual addiction and a low interest in sex as an adult have their origins during childhood and adolescence. Adult interest in sex and the likelihood of engaging in risky sexual behaviors tended to be increased if participant's first experiences with masturbation and partner sex had occurred early in life. Conversely, adult interest in sex tended to be lowest when neither masturbation nor sex with a partner had occurred prior to 18 years of age. Both findings were consistent with critical period learning.

The results of our study provided a new theoretical and developmental basis for both origins of sexual addiction on the one hand and hypoactive sexual desire on the other hand. The higher interest in sex observed in those who had early experience with partner sex and masturbation can be explained by the combined action of Pavlovian conditioning, operant conditioning, and critical period learning initiated by early experience with partner sex with or without the synergistic effect of an early experience with masturbation (Beard et al., 2013; O’Keefe et al., 2014; also see Hoffmann, 2012 and Pfaus et al., 2012 for reviews of conditioning theories and experimental data).

4) Korean Men’s Pornography use, Their Interest in Extreme Pornography, and Dyadic Sexual Relationships (2014) – Excerpt:

The majority (84.5%) of respondents had viewed pornography, and for those who were sexually active (470 respondents), we found that higher interest in degrading or extreme pornography was associated with the experience of role-playing sexual scenes from pornography with a partner, and a preference for using pornography to achieve and maintain sexual excitement over having sex with a partner.

5) Human Sexual Development is Subject to Critical Period Learning: Implications for Sexual Addiction, Sexual Therapy, and for Child Rearing (2014) – Excerpt:

A novel orientation-neutral Hypersexuality and Risky Sexual Behaviors Scale provided evidence consistent with the idea that both sexual addiction and a low interest in sex as an adult have their origins during childhood and adolescence. Adult interest in sex and the likelihood of engaging in risky sexual behaviors tended to be increased if participant's first experiences with masturbation and partner sex had occurred early in life. Conversely, adult interest in sex tended to be lowest when neither masturbation nor sex with a partner had occurred prior to 18 years of age. Both findings were consistent with critical period learning.

The results of our study provided a new theoretical and developmental basis for both origins of sexual addiction on the one hand and hypoactive sexual desire on the other hand. The higher interest in sex observed in those who had early experience with partner sex and masturbation can be explained by the combined action of Pavlovian conditioning, operant conditioning, and critical period learning initiated by early experience with partner sex with or without the synergistic effect of an early experience with masturbation (Beard et al., 2013; O’Keefe et al., 2014; also see Hoffmann, 2012 and Pfaus et al., 2012 for reviews of conditioning theories and experimentadata).

6)  “Without Porn … I Wouldn't Know Half the Things I Know Now”: A Qualitative Study of Pornography Use Among a Sample of Urban, Low-Income, Black and Hispanic Youth (2015) – Excerpt:

In addition, our findings highlighted that some youth use pornography as an instructional resource: youth sought out pornography to learn how to have sex; others either imitated or were asked by a partner to imitate, what they saw. Our finding that youth imitate what they see in pornography is consistent with at least one prior study of 51 pornography viewing youth who reported that they copied what they saw in pornography when they had sex (Smith, 2013), and a quantitative study that found 63% of a sample of college students reported learning new sexual techniques from pornography (Trostle, 2003). In the present study using pornography as a model for sexual activity had negative consequences for some females in the sample who reported being “stunned” by pain from anal sex, feeling forced to have sex in an uncomfortable position, not enjoying sex, or faking sexual response. These results are consistent with those reported by Marston and Lewis (2014), who found that in a sample of 130 youth ages 16 to 18 years old women reported finding anal sex painful but were often “badgered” into it by male partners, and that youth felt that interest in anal sex was primarily attributable to pornography.

7) Exploring the effect of sexually explicit material on the sexual beliefs, understanding and practices of young men: a qualitative survey (2016) – Excerpt:

The results highlight some potentially important findings in relation to the effect SEM consumption has on the sexual beliefs, understanding and practices of young men, an under researched field.  Within the limitations of a qualitative and therefore non generalizable sample, themes would benefit from large sample confirmation but still contribute to the beginnings of a theoretical account of how SEM can shape attitudes and behaviour. Consumption and acceptance SEM was reported as growing, as confirmed in other research (2,3,4,16,10)., including more extreme content as  adolescents reported becoming desensitised to SEM content, requiring evermore extreme exposure in order to feel stimulated or shocked.  

Young men in this study, acknowledged negative effects on the sexual attitudes and behaviours of adolescents. Young men in this study themselves raised the possibility that SEM exposure may lead to an addiction model of consumption with increasing need for more extreme content. Some report feeling the need to constantly push their boundaries for stimulation, with individuals no longer being shocked by some content, a pattern found in previous research(32, 33, 34, 35, 36) linking it to premature sexual experiences; objectification of females, unrealistic expectations and  increased incidence of sexual harassment (16).

8) Sexual Scripts and the Sexual Behavior of Men and Women Who Use Pornography (2016) – Excerpt:

Using data collected from 1,880 heterosexual men and women residing in the United States, this study investigated the associations among gender, pornography consumption, and 20 sexual behaviors observed in popular pornography. Acts were grouped according to whether participants reported engaging or being interested in trying specific sexual behaviors as the (a) aggressor (e.g., hairpulling, spanking, or choking), (b) target (e.g., being spanked or choked), or (c) uncommon and/or degrading sexual activity (e.g., male ejaculation in female partner’s mouth, anal sex, double penetration, and ass-to-mouth). Using sexual script theory, we hypothesized greater use of pornography would be associated with greater likelihood of both having engaged in and interest in engaging in these sexual behaviors. Higher pornography use was associated with greater likelihood of both engaging and being interested in trying all categories of sexual behavior. Men were more likely than women to have engaged in aggressive and degrading/uncommon behaviors, and women were more likely than men to have engaged in target behaviors.

9) The Relationship between Frequent Pornography Consumption, Behaviors, and Sexual Preoccupancy among Male Adolescents in Sweden (2017) – Excerpt:

Our findings show that frequent users more often report behaviours associated with sexual risk taking including earlier age at sexual debut, anal sex, and having tried acts seen in pornography

Based on the 3AM, if frequent users are more likely to test out sexual acts seen in pornography, it is not far-fetched to presume that the risky manner in which they have seen the acts performed might also be internalized (acquired) and applied (application) in real-life scenarios.

With regards to compulsive pornography consumption, it is striking that one-third of frequent users admitted they watch pornography more than they want to. As stated above, a growing body of empirical research considers pornography potentially addictive. Since adolescents’ brains are still in their development phase, young people may be especially vulnerable to problematic pornography use. “Unlike adults, adolescents are believed to lack sufficient maturation and integrity in frontal cortices necessary to exert cognitive control required to suppress sexual cravings, thoughts, and behaviours elicited by pornographic content.” This, combined with the notion that adolescents process and retain images far better than written or spoken words, means that the development of relevant, effective sexual education becomes all the more crucial to counterbalance the messages in the pornography ‘script’.

Results indicate that frequent users of pornography have sexual debuts at younger ages, engage in a broader range of sexual encounters, and are more likely to struggle with sexual preoccupancy and problematic pornography use. This study contributes to a growing body of research providing evidence that pornography may have negative effects on adolescents.

In 2012, the porn recovery subreddit Nofap conducted a very large survey. One of the questions asked about escalation: "Did your tastes in pornography change?" The results:

  • My tastes did not change significantly - 29%
  • My tastes became increasingly extreme or deviant and this caused me to feel shame or stress - 36%
  • My tastes became increasingly extreme or deviant and this did not cause me to feel shame or stress - 27%

In summary, the vast preponderance of empirical and other data supports the claim that internet porn can shape sexual tastes or sexual behaviors, especially during adolescence. The suggestion that sexual tastes can be profoundly re-conditioned is not theoretical, as animal and human studies have revealed. From the review Neuroscientific Approaches to Online Pornography Addiction (2017), an excerpt discussing pornography and sexual conditioning:

7.3.2 Cue Reactivity and Appetitive Conditioning

In the last section, we have reviewed the studies regarding brain responses toward sexual material, cue reactivity, and appetitive conditioning and finally also the neurophysiological correlates of excessive pornography consumption. We could demonstrate that sexual stimuli induce neural activation in the reward circuit (e.g., ACC, ventral striatum, orbitofrontal cortex), probably due to the mesolimbic dopamine reward pathway. Thus, the hypothesis that the consumption of pornography might be appetitive for most men is confirmed. The appetitive value of pornographic material is further underlined by the fact that these stimuli can be used as unconditioned stimuli in appetitive conditioning experiments. Therefore—similar to other addictions—formally neutral stimuli become triggers of the addictive behavior. This is in accordance with reports of men with pornography addiction describing a strong urge/craving to consume pornography if confronted with certain situations, feelings, or stimuli which share similarities with situations, in which pornography is usually consumed. Especially stimuli with sexual aspects, for example a cover of a magazine, but also context information like being alone-at-home might elicit the urge for addictive behavior.

In substance-related addictions, cue reactivity delineates the observation that formerly neutral stimuli which became associated with drug intake trigger craving by dopamine release in the ventral striatum even if the stimuli are backward masked (Childress et al. 2008). The underlying mechanism is appetitive conditioning, a form of classical conditioning (Martin-Soelch et al. 2007). It is assumed that appetitive conditioning is also involved in sexual behavior, e.g., the development of sexual preferences (Akins 2004; Brom et al. 2014; Martin-Soelch et al. 2007; Pfaus et al. 2001) and also plays a major role in sexual addiction (Banca et al. 2016; Klucken et al. 2016). Interestingly, although appetitive conditioning is assumed to be a central mechanism of the development of addiction, only few studies to date have examined the neural correlates of appetitive conditioning, especially in context of sexual addiction.

In case of pornography addiction, one assumes that internal (e.g., arousal, negative mood) or external (e.g., the view of a computer or smartphone) stimuli which were associated with pornography use and masturbation in the past trigger the currently addictive behavior. This hypothesis requires that pornography can indeed serve as unconditioned stimuli in an appetitive conditioning paradigm resulting in a conditioned dopaminergic-driven neural response in the ventral striatum toward the conditioned stimuli.

In typical appetitive conditioning experiments, a neutral stimulus (later the conditioned stimulus, CS+) is paired with a reward (unconditioned stimulus, UCS) like money, pleasant odors, drug, or sexual stimuli, while a second neutral stimulus (CS−) is associated with the absence of the UCS (Martin-Soelch et al. 2007). By testing the differential responses toward CS+ and CS−, differential appetitive conditioning can be proven. There are several studies that have used this experimental design with sexual stimuli as unconditioned stimuli (Both et al. 2008, 2011; Klucken et al. 2009, 2013, 2015). These studies have repeatedly shown that the CS+, which is paired with sexual stimuli (e.g., sexual pictures or genital stimulation), elicits conditioned responses (i.e., increased responses to the CS+ in contrast to the CS−). For instance, increased preference and arousal ratings were found to the CS+ in contrast to the CS− after conditioning but not before (Klucken et al. 2009, 2013). However, while changes in preference ratings have repeatedly been found during appetitive conditioning, conditioned responses in other response systems like peripheral-physiological responses (e.g., skin conductance responses (SCRs) or genital responses) are less clear. For instance, Klucken et al. (2009) found increased subjective ratings and hemodynamic responses to the CS+ compared with the CS−, but no significant differences in SCRs. Moreover, the same subjects reliably differed in SCRs between the UCS (sexual pictures) and the non-UCS (neutral, nonsexual pictures), highlighting that SCRs are able to differ between salient and non-salient stimuli in general. However, other studies using a higher number of subjects could demonstrate increased conditioned SCRs toward the CS+ (Klucken et al. 2013). To interpret these diverging results, it is hypothesized that the conditioned effects in psychophysiological responses are smaller and may also depend more on individual differences (Klucken et al. 2009, 2013, 2015). In a review, Brom et al. (2014) also assume that peripheral-physiological responses may not be a strong marker for appetitive conditioning, especially in context of sexual stimuli.

With respect to the neural correlates of appetitive conditioning with sexual stimuli as UCS, studies have identified a subcortical and cortical network including the amygdala, the ventral striatum, the orbitofrontal cortex (OFC), the anterior cingulated cortex (ACC), and the insula (Martin-Soelch et al. 2007). One of the most important structures for appetitive conditioning is the amygdala, which is crucially involved in the formation of the CS–UCS association (Martin-Soelch et al. 2007). Day and Carelli (2007) emphasize in their review the ventral striatum, or more specifically, the nucleus accumbens as key regions for appetitive conditioning. This important role of the ventral striatum in appetitive conditioning is also supported by findings, showing its involvement in the processing and the anticipation of positive events especially sexual arousal (Oei et al. 2012; Stark et al. 2005). OFC, insula, and ACC activations may reflect conscious evaluation processes of the current CS value and are also important for the awareness of bodily sensations, which seems to be irrespective of sexual stimuli, other emotions like fear and disgust, or other rewarding stimuli (Craig 2009; Domjan 1994; Klucken et al. 2009). Interestingly, studies investigating appetitive conditioning processes in subjects with sexual addiction found small differences to healthy control subjects only. In one of our own studies, Klucken et al. (2016) found increased amygdala activation in sex addicted subjects as well as decreased striatal/prefrontal connectivity during appetitive conditioning even after correcting for individual pleasantness ratings. One explanation for these group differences is the assumption that the increased amygdala activation mirrors facilitated conditioning and craving processes in men with sexual addiction. In addition, the decreased striatal/prefrontal connectivity may reflect impaired emotion-regulation processes like an impeded downregulation of craving in these patients.

In sum, knowledge about appetitive conditioning with sexual stimuli is limited. The few so far published studies showed the same neural network involved in other appetitive conditioning processes with nonsexual rewarding stimuli with the NAcc as one of the most important structures. However, one interesting perspective to explore is the time course of the dopamine activation, because there is some evidence that dopamine in the NAcc plays an important role in the beginning, but less in the sustained sexual behavior (Georgiadis et al. 2012).

The following excerpt from Park et al., 2016 summarizes some of the human and animal research as it relates to internet pornography conditioning sexual arousal:

3.4.3. Internet Pornography and Sexual Conditioning

Given that our servicemen reported that they experienced erections and arousal with Internet pornography, but not without it, research is needed to rule out inadvertent sexual conditioning as a contributing factor to today’s rising rates of sexual performance problems and low sexual desire in men under 40. Prause and Pfaus have hypothesized that sexual arousal may become conditioned to aspects of Internet pornography use that do not readily transition to real-life partner situations. “It is conceivable that experiencing the majority of sexual arousal within the context of VSS [visual sexual stimuli] may result in a diminished erectile response during partnered sexual interactions...When high stimulation expectations are not met, partnered sexual stimulation is ineffective” [50]. Such inadvertent sexual conditioning is consistent with the incentive-salience model. Several lines of research implicate increased mesolimbic dopamine in sensitization to both drugs of abuse and sexual reward [100,103]. Acting through dopamine D1 receptors, both sexual experience and psychostimulant exposure induce many of the same long-lasting neuroplastic changes in the NAc critical for enhanced wanting of both rewards [103].

Today’s Internet pornography user can maintain high levels of sexual arousal, and concomitant elevated dopamine, for extended periods due to unlimited novel content. High dopamine states have been implicated in conditioning sexual behavior in unexpected ways in both animal models [176,177] and humans. In humans, when Parkinson’s patients were prescribed dopamine agonists, some reported uncharacteristic compulsive pornography use and demonstrated greater neural activity to sexual picture cues, correlating with enhanced sexual desire [178]. Two recent fMRI studies reported that subjects with compulsive sexual behaviors are more prone to establish conditioned associations between formally neutral cues and explicit sexual stimuli than controls [86,121]. With repeated Internet pornography exposure, “wanting” may increase for Internet pornography’s expected novelty and variety, elements difficult to sustain during partnered sex. In line with the hypothesis that Internet pornography use can condition sexual expectations, Seok and Sohn found that compared to controls hypersexuals had greater DLPFC activation to sexual cues, yet less DLPFC activation to non-sexual stimuli [120]. It also appears that Internet pornography use can condition the user to expect or “want” novelty. Banca et al. reported that subjects with compulsive sexual behaviors had greater preference for novel sexual images and showed greater habituation in the dorsal anterior cingulate cortex to repeated viewing of the same sexual images [86]. In some users, a preference for novelty arises from the need to overcome declining libido and erectile function, which may, in turn, lead to new conditioned pornographic tastes [27].

When a user has conditioned his sexual arousal to Internet pornography, sex with desired real partners may register as “not meeting expectations” (negative reward prediction) resulting in a corresponding decline in dopamine. Combined with the inability to click to more stimulation, this unmet prediction may reinforce an impression that partnered sex is less salient than Internet pornography use. Internet pornography also offers a voyeur's perspective generally not available throughout partnered sex. It is possible that if a susceptible Internet pornography user reinforces the association between arousal and watching other people have sex on screens while he is highly aroused, his association between arousal and real-life partnered sexual encounters may weaken.

Research on conditioning of sexual response in humans is limited, but shows that sexual arousal is conditionable [179,180,181], and particularly prior to adulthood [182]. In men, arousal can be conditioned to particular films [183], as well as to images [184]. Sexual performance and attraction in male (non-human) animals can be conditioned to an array of stimuli that are not typically sexually salient for them, including fruit/nut scents, aversive scents, such as cadaverine, same-sex partners, and the wearing of rodent jackets [177,185,186,187]. For example, rats that had learned sex with a jacket did not perform normally without their jackets [187].

In line with these conditioning studies, the younger the age at which men first began regular use of Internet pornography, and the greater their preference for it over partnered sex, the less enjoyment they report from partnered sex, and the higher their current Internet pornography use [37]. Similarly, men reporting increased consumption of bareback anal pornography (in which actors do not wear condoms) and its consumption at an earlier age, engage in more unprotected anal sex themselves [188,189]. Early consumption of pornography may also be associated with conditioning tastes to more extreme stimulation [99,190].

A review by Pfaus points to early conditioning as critical for sexual arousal templates: “It is becoming increasingly clear that there is a critical period of sexual behavior development that forms around an individual’s first experiences with sexual arousal and desire, masturbation, orgasm, and sexual intercourse itself” [191] (p. 32). The suggestion of a critical developmental period is consistent with the report of Voon et al. that younger compulsive Internet pornography users showed greater activity in the ventral striatum in response to explicit videos [31]. The ventral striatum is the primary region involved in sensitization to natural and drug reward [103]. Voon et al. also reported that compulsive Internet pornography subjects first viewed Internet pornography much earlier (mean age 13.9) than healthy volunteers (mean age 17.2) [31]. A 2014 study found that nearly half of college-age men now report they were exposed to Internet pornography prior to age 13, as compared with only 14% in 2008 [37]. Could increased Internet pornography use during a critical developmental phase increase the risk of Internet pornography-related problems? Might it help explain the 2015 finding that 16% of young Italian men who used Internet pornography more than once a week reported low sexual desire, compared with 0% in non-consumers [29]? Our first serviceman was only 20 and had been using Internet pornography since he gained access to high-speed Internet.

Males can successfully condition their sexual response in the laboratory with instructional feedback, but without further reinforcement, such laboratory-induced conditioning disappears in later trials [176]. This inherent neuroplasticity may suggest how two of our servicemen restored attraction and sexual performance with partners after abandoning a sex toy and/or cutting back on Internet pornography. Decreasing or extinguishing conditioned responses to artificial stimuli potentially restored attraction and sexual performance with partners.

Finally, here are additional excerpts from a Norman Doidge article published in a peer-reviewed journal: Sex on the Brain: What Brain Plasticity Teaches About Internet Porn (2014).

We are in the midst of a revolution in sexual and romantic tastes unlike any other in history, a social experiment being performed on children and teenagers, captured in a powerful, poignant scene in the recent British documentary InRealLife, about the effects of the internet on teenagers, directed by Baroness Beeban Kidron.

In the film, a 15-year-old boy of impressive frankness articulates a process that is going on in the lives of millions of teen boys, whose sexual tastes are being shaped in large part by their 24/7 access to internet porn. He describes how porn images have moulded his “real life” sexual activity:

“You’d try out a girl and get a perfect image of what you’ve watched on the internet … you’d want her to be exactly like the one you saw on the internet … I’m highly thankful to whoever made these websites, and that they’re free, but in other senses it’s ruined the whole sense of love. It hurts me because I find now it’s so hard for me to actually find a connection to a girl.”

What is so poignant about the scene, is how he has at a young age discovered that his sexual tastes and romantic longings have become dissociated from each other.

Meanwhile, we learn from this and other films that the girls who are the potential mates of such boys, have “downloaded” on to them the expectation that they play “roles” written by pornographers.

The teenager’s distress represents one of the paradoxes of porn. Why should it make it hard for him to be turned on by a girl, and not easier? Once, porn was used by teens to explore, prepare and relieve sexual tension, in anticipation of a real sexual relationship. Today, there is something about the new, internet-based forms of porn that causes porn not to prepare a person for a sexual relationship, but rather to supplant it. Many young men even say they prefer it to sex and relationships with people, with all their hassles. Perhaps these are the grumblings of boys, low in the dominance hierarchy, unable to “get” a girl. But some, like the able teen in the film, find that even though they can “get” a girl, when they do, their sexuality is “not working right”.

We are in the midst of a revolution in sexual and romantic tastes unlike any other in history, a social experiment being performed on children and teenagers, captured in a powerful, poignant scene in the recent British documentary InRealLife, about the effects of the internet on teenagers, directed by Baroness Beeban Kidron.

In the film, a 15-year-old boy of impressive frankness articulates a process that is going on in the lives of millions of teen boys, whose sexual tastes are being shaped in large part by their 24/7 access to internet porn. He describes how porn images have moulded his “real life” sexual activity:

“You’d try out a girl and get a perfect image of what you’ve watched on the internet … you’d want her to be exactly like the one you saw on the internet … I’m highly thankful to whoever made these websites, and that they’re free, but in other senses it’s ruined the whole sense of love. It hurts me because I find now it’s so hard for me to actually find a connection to a girl.”

What is so poignant about the scene, is how he has at a young age discovered that his sexual tastes and romantic longings have become dissociated from each other.

The teenager’s distress represents one of the paradoxes of porn. Why should it make it hard for him to be turned on by a girl, and not easier? Once, porn was used by teens to explore, prepare and relieve sexual tension, in anticipation of a real sexual relationship. Today, there is something about the new, internet-based forms of porn that causes porn not to prepare a person for a sexual relationship, but rather to supplant it. Many young men even say they prefer it to sex and relationships with people, with all their hassles. Perhaps these are the grumblings of boys, low in the dominance hierarchy, unable to “get” a girl. But some, like the able teen in the film, find that even though they can “get” a girl, when they do, their sexuality is “not working right”.

The young man’s complaint had a familiar ring, albeit with a twist. In the mid-1990s I, and other psychiatrists, began to notice the following pattern. The typical example would be an adult male, in a happy relationship, who described getting curious about porn on the burgeoning internet. Most sites he found boring, but he soon noticed several that fascinated him to the point that he began craving them. The more he used the porn, the more he wanted to. The problem was not just the time spent on the internet. He had now acquired a taste for a kind of pornography that, to a greater or lesser degree, ultimately affected his relationships and sexual potency…


SLIDE 33

As a guy returns to normal sensitivity, his brain looks around for the rewards it evolved to seek--including friendly interaction and real mates. Here’s one more example of what we hear every day:

ORIGINAL SUPPORT:

The core concept of slide 33 is that internet porn negatively affects intimate relationships. As with a few previous slides The Great Porn Experiment leaned on thousands of self-reports by men who had eliminated porn and experienced renewed attraction to real partners, greater arousal with partners, and much better sex. Many such accounts can be found on these pages (also see the comments sections below articles):

In addition to self-reports and clinical evidence, by 2012 many studies had been published linking porn use to poorer sexual and relationship satisfaction:

1) Effect of Erotica on Young Men's Aesthetic Perception of Their Female Sexual Partners (1984) - Excerpt:

Male undergraduates were exposed to (a) nature scenes or (b) beautiful versus (c) unattractive females in sexually enticing situations. Thereafter, they assessed their girl friends' sexual appeal and evaluated their satisfaction with their mates. On pictorial measures of bodily appeal profiles of flat through hypervoluptuous breast and buttock, preexposure to beautiful females tended to suppress mates' appeal, while preexposure to unattractive females tended to enhance it. After exposure to beautiful females, mates' aesthetic value fell significantly below assessments made after exposure to unattractive females; this value assumed an intermediate position after control exposure. Changes in mates' aesthetic appeal did not correspond with changes in satisfaction with mates, however.

2) Effects of Prolonged Consumption of Pornography on Family Values (1988) - Excerpt:

Male and female students and nonstudents were exposed to videotapes featuring common, nonviolent pornography or innocuous content. Exposure was in hourly sessions in six consecutive weeks. In the seventh week, subjects participated in an ostensibly unrelated study on societal institutions and personal gratifications. Marriage, cohabitational relationships, and related issues were judged on an especially created Value-of-Marriage questionnaire. The findings showed a consistent impact of pornography consumption. Exposure prompted, among other things, greater acceptance of pre- and extramarital sex and greater tolerance of nonexclusive sexual access to intimate partners. It enhanced the belief that male and female promiscuity are natural and that the repression of sexual inclinations poses a health risk. Exposure lowered the evaluation of marriage, making this institution appear less significant and less viable in the future. Exposure also reduced the desire to have children and promoted the acceptance of male dominance and female servitude. With few exceptions, these effects were uniform for male and female respondents as well as for students and nonstudents.

3) Pornography’s Impact on Sexual Satisfaction (1988) - Excerpt:

Male and female students and nonstudents were exposed to videotapes featuring common, nonviolent pornography or innocuous content. Exposure was in hourly sessions in six consecutive weeks. In the seventh week, subjects participated in an ostensibly unrelated study on societal institutions and personal gratifications. [Porn use] strongly impacted self-assessment of sexual experience. After consumption of pornography, subjects reported less satisfaction with their intimate partners—specifically, with these partners' affection, physical appearance, sexual curiosity, and sexual performance proper. In addition, subjects assigned increased importance to sex without emotional involvement. These effects were uniform across gender and populations.

4) Influence of popular erotica on judgments of strangers and mates (1989) - Excerpt:

In Experiment 2, male and female subjects were exposed to opposite sex erotica. In the second study, there was an interaction of subject sex with stimulus condition upon sexual attraction ratings. Decremental effects of centerfold exposure were found only for male subjects exposed to female nudes. Males who found the Playboy-type centerfolds more pleasant rated themselves as less in love with their wives.

5)  Men’s leisure and women’s lives: The impact of pornography on women (1999) - Excerpt:

The section of the interview where the women discussed their own current or past relationships with men revealed additional insight into the effect of pornography on such relationships. Fifteen of the women were in, or had been in, relationships with men who rented or bought pornography at least on an occasional basis. Of these 15 women, four expressed strong dislike of their husband’s or partner’s leisure time interest in pornography. It was clear that the husbands’ use of pornography affected the wives’ feeling about themselves, their sexual feelings, and their marital relationships in general

6) Adult Social Bonds and Use of Internet Pornography (2004) - Excerpt:

Complete data on 531 Internet users are taken from the General Social Surveys for 2000. Social bonds measures include religious, marital, and political ties. Measures of participation in sexual and drug-related deviant lifestyles, and demographic controls are included. The results of a logistic regression analysis found that among the strongest predictors of use of cyberporn were weak ties to religion and lack of a happy marriage.

7) Sex in America Online: An Exploration of Sex, Marital Status, and Sexual Identity in Internet Sex Seeking and Its Impacts (2008) - Excerpt:

This was an exploratory study of sex and relationship seeking on the Internet, based on a survey of 15,246 respondents in the United States Seventy-five percent of men and 41% of women had intentionally viewed or downloaded porn. Men and gays/lesbians were more likely to access porn or engage in other sex-seeking behaviors online compared with straights or women. A symmetrical relationship was revealed between men and women as a result of viewing pornography, with women reporting more negative consequences, including lowered body image, partner critical of their body, increased pressure to perform acts seen in pornographic films, and less actual sex, while men reported being more critical of their partners' body and less interested in actual sex.

8) Adolescents’ Exposure to Sexually Explicit Internet Material and Sexual Satisfaction: A Longitudinal Study (2009) - Excerpt:

Between May 2006 and May 2007, we conducted a three-wave panel survey among 1,052 Dutch adolescents aged 13–20. Structural equation modeling revealed that exposure to SEIM consistently reduced adolescents’ sexual satisfaction. Lower sexual satisfaction (in Wave 2) also increased the use of SEIM (in Wave 3). The effect of exposure to SEIM on sexual satisfaction did not differ among male and female adolescents.

9) Wives' Experience of Husbands' Pornography Use and Concomitant Deception as an Attachment Threat in the Adult Pair-Bond Relationship (2009) - Excerpt:

Evidence is growing that pornography use can negatively impact attachment trust in the adult pair-bond relationship. Analyses uncovered three attachment-related impacts from husbands' pornography use and deception: (1) the development of an attachment fault line in the relationship, stemming from perceived attachment infidelity; (2) followed by a widening attachment rift arising from wives' sense of distance and disconnection from their husbands; (3) culminating in attachment estrangement from a sense of being emotionally and psychologically unsafe in the relationship. Overall, wives reported global mistrust indicative of attachment breakdown.

10) Sexual media use and relational satisfaction in heterosexual couples (2010) - Excerpt:

Results revealed that a higher frequency of men's sexual media use related to negative satisfaction in men, while a higher frequency of women's sexual media use related to positive satisfaction in male partners. Reasons for sexual media use differed by gender: Men reported primarily using sexual media for masturbation, while women reported primarily using sexual media as part of lovemaking with their partners.

11) Exploring actor and partner correlates of sexual satisfaction among married couples (2010) - Excerpt:

Using the Interpersonal Exchange Model of Sexual Satisfaction, we consider how infidelity, pornography consumption, marital satisfaction, sexual frequency, premarital sex, and cohabitation are associated with married couples’ sexual satisfaction. Data from 433 couples are analyzed with structural equation models to determine the contributions. Finally, some evidence suggests that pornography consumption is costly for own and spouse’s sexual satisfaction, especially when pornography is used by only one spouse.

12) Individuals who never viewed SEM reported higher relationship quality on all indices than those who viewed SEM alone (2011) - Excerpt:

As expected, individuals who did not view SEM (sexually explicit material) at all reported lower negative communication and higher dedication than individuals who viewed SEM alone or both alone and with their partner.

13) Sexual media use and relational satisfaction in heterosexual couples (2011) - Excerpt:

This study assessed how sexual media use by one or both members of a romantic dyad relates to relationship and sexual satisfaction. A total of 217 heterosexual couples completed an Internet survey that assessed sexual media use, relationship and sexual satisfaction, and demographic variables. Results revealed that a higher frequency of men's sexual media use related to negative satisfaction in men, while a higher frequency of women's sexual media use related to positive satisfaction in male partners. Reasons for sexual media use differed by gender

14) Associations between young adults’ use of sexually explicit materials and their sexual preferences, behaviors, and satisfaction (2011) - Excerpts:

Higher frequencies of sexual explicit material (SEM) use were associated with less sexual and relationship satisfaction. The frequency of SEM use and number of SEM types viewed were both associated with higher sexual preferences for the types of sexual practices typically presented in SEM. These findings suggest that SEM use can play a significant role in a variety of aspects of young adults' sexual development processes.

Specifically, higher viewing frequency was associated with less sexual and relationship satisfaction when controlling for gender, religiosity, dating status and the number of SEM types viewed.

Because a substantial proportion of the young adults in this study reported using SEM, the potential implications are especially noteworthy, particularly for young men.

15) Viewing Sexually-Explicit Materials Alone or Together: Associations with Relationship Quality (2011) - Excerpt:

This study investigated associations between viewing sexually-explicit material (SEM) and relationship functioning in a random sample of 1291 unmarried individuals in romantic relationships. More men (76.8%) than women (31.6%) reported that they viewed SEM on their own, but nearly half of both men and women reported sometimes viewing SEM with their partner (44.8%).  Individuals who never viewed SEM reported higher relationship quality on all indices than those who viewed SEM alone. Those who viewed SEM only with their partners reported more dedication and higher sexual satisfaction than those who viewed SEM alone. The only difference between those who never viewed SEM and those who viewed it only with their partners was that those who never viewed it had lower rates of infidelity.

UPDATED SUPPORT:

As of 2017, at least fifty-five studies have linked porn use to poorer sexual and relationship satisfaction. While a few studies correlated greater porn use in females to greater sexual satisfaction, most have not (see this list - Porn studies involving female subjects: Negative effects on arousal, sexual satisfaction, and relationships). As far as I know all studies involving males have reported porn use linked to poorer sexual or relationship satisfaction.

In the list below, study #1 is a meta-analysis, study #2 had porn users attempt to quit using porn for 3 weeks, and studies 3 through 7 are longitudinal:

1) Pornography Consumption and Satisfaction: A Meta-Analysis (2017) - This meta-analysis of various other studies assessing sexual and relationship satisfaction reported that porn use was consistently related to lower sexual and relationship satisfaction (interpersonal satisfaction). While some studies report little negative effect of porn use on sexual and relationship satisfaction in women, it's important to know that a relatively small percentage of coupled females (across the population) regularly consume internet porn. Cross-sectional data from the largest US survey (General Social Survey) suggest that only 2.6% of women had visited a "pornographic website" in the last month (2002-2004). An excerpt:

However, pornography consumption was associated with lower interpersonal satisfaction outcomes in cross-sectional surveys, longitudinal surveys, and experiments. Associations between pornography consumption and reduced interpersonal satisfaction outcomes were not moderated by their year of release or their publication status. But analyses by sex indicted significant results for men only.

2) A Love That Doesn’t Last: Pornography Consumption and Weakened Commitment to One’s Romantic Partner (2012) – The study had subjects try to abstain from porn use for 3 weeks. Upon comparing the two groups, those who continued using pornography reported lower levels of commitment than those who tried to abstain. Excerpts:

Study 1 found that higher pornography consumption was related to lower commitment

Study 3 participants were randomly assigned to either refrain from viewing pornography or to a self-control task. Those who continued using pornography reported lower levels of commitment than control participants.

Study 5 found that pornography consumption was positively related to infidelity and this association was mediated by commitment. Overall, a consistent pattern of results was found using a variety of approaches including cross-sectional (Study 1), observational (Study 2), experimental (Study 3), and behavioral (Studies 4 and 5) data.

3) Internet pornography and relationship quality: A longitudinal study of within and between partner effects of adjustment, sexual satisfaction and sexually explicit internet material among newly-weds (2015) - Excerpt:

The data from a considerable sample of newlyweds showed that SEIM use has more negative than positive consequences for husbands and wives. Importantly, husbands’ adjustment decreased SEIM use over time and SEIM use decreased adjustment. Furthermore, more sexual satisfaction in husbands predicted a decrease in their wives’ SEIM use one year later, while wives’ SEIM use did not change their husbands’ sexual satisfaction.

4) Does Viewing Pornography Reduce Marital Quality Over Time? Evidence from Longitudinal Data (2016) - First longitudinal study on a representative cross-section of married couples. It found significant negative effects of porn use on marriage quality over time.  Excerpt:

This study is the first to draw on nationally representative, longitudinal data (2006-2012 Portraits of American Life Study) to test whether more frequent pornography use influences marital quality later on and whether this effect is moderated by gender. In general, married persons who more frequently viewed pornography in 2006 reported significantly lower levels of marital quality in 2012, net of controls for earlier marital quality and relevant correlates. Pornography's effect was not simply a proxy for dissatisfaction with sex life or marital decision-making in 2006. In terms of substantive influence, frequency of pornography use in 2006 was the second strongest predictor of marital quality in 2012

5) Till Porn Do Us Part? Longitudinal Effects of Pornography Use on Divorce (2017) - This longitudinal study used nationally representative General Social Survey panel data collected from thousands of American adults. Respondents were interviewed three times about their pornography use and marital status -- every two years from 2006-2010, 2008-2012, or 2010-2014. Excerpts:

Beginning pornography use between survey waves nearly doubled one's likelihood of being divorced by the next survey period, from 6 percent to 11 percent, and nearly tripled it for women, from 6 percent to 16 percent. Our results suggest that viewing pornography, under certain social conditions, may have negative effects on marital stability. Conversely, discontinuing pornography use between survey waves was associated with a lower probability of divorce, but only for women.

Additionally, the researchers found that respondents' initially reported level of marital happiness played an important role in determining the magnitude of pornography's association with the probability of divorce. Among people who reported they were "very happy" in their marriage in the first survey wave, beginning pornography viewership before the next survey was associated with a noteworthy increase -- from 3 percent to 12 percent -- in the likelihood of getting divorced by the time of that next survey.

Additional analyses also showed that the association between beginning pornography use and the probability of divorce was particularly strong among younger Americans, those who were less religious, and those who reported greater initial marital happiness.

6) Pornography Use and Marital Separation: Evidence from Two-Wave Panel Data (2017) – Longitudinal study. Excerpts:

Drawing on data from the 2006 and 2012 waves of the nationally representative Portraits of American Life Study, this article examined whether married Americans who viewed pornography in 2006, either at all or in greater frequencies, were more likely to experience a marital separation by 2012. Binary logistic regression analyses showed that married Americans who viewed pornography at all in 2006 were more than twice as likely as those who did not view pornography to experience a separation by 2012, even after controlling for 2006 marital happiness and sexual satisfaction as well as relevant sociodemographic correlates. The relationship between pornography use frequency and marital separation, however, was technically curvilinear. The likelihood of marital separation by 2012 increased with 2006 pornography use to a point and then declined at the highest frequencies of pornography use.

7) Are Pornography Users More Likely to Experience A Romantic Breakup? Evidence from Longitudinal Data (2017) – Longitudinal study. Excerpts:

This study examined whether Americans who use pornography, either at all or more frequently, are more prone to report experiencing a romantic breakup over time. Longitudinal data were taken from the 2006 and 2012 waves of the nationally representative Portraits of American Life Study. Binary logistic regression analyses demonstrated that Americans who viewed pornography at all in 2006 were nearly twice as likely as those who never viewed pornography to report experiencing a romantic breakup by 2012, even after controlling for relevant factors such as 2006 relationship status and other sociodemographic correlates. This association was considerably stronger for men than for women and for unmarried Americans than for married Americans. Analyses also showed a linear relationship between how frequently Americans viewed pornography in 2006 and their odds of experiencing a breakup by 2012.

8) Young Adult Women’s Reports of Their Male Romantic Partner’s Pornography Use as a Correlate of Their Self-Esteem, Relationship Quality, and Sexual Satisfaction (2012) - Excerpt:

The purpose of this study was to examine the relationships between men’s pornography use, both frequency and problematic use, on their heterosexual female partner’s psychological and relational well-being among 308 young adult college women. Results revealed women’s reports of their male partner’s frequency of pornography use were negatively associated with their relationship quality. More perceptions of problematic use of pornography was negatively correlated with self-esteem, relationship quality, and sexual satisfaction.

9) Pornography use: who uses it and how it is associated with couple outcomes (2013) - Excerpt:

This study examined associations among pornography use, the meaning people attach to its use, sexual quality, and relationship satisfaction. Participants were couples (N = 617 couples) who were either married or cohabiting at the time the data were gathered. Overall results from this study indicated substantial gender differences in terms of use profiles, as well as pornography's association with relationship factors. Specifically, male pornography use was negatively associated with both male and female sexual quality, whereas female pornography use was positively associated with female sexual quality.

10) Internet Pornography Exposure and Women's Attitude Towards Extramarital Sex: An Exploratory Study (2013) - Excerpt:

This exploratory study assessed the association between adult U.S. women's exposure to Internet pornography and attitude towards extramarital sex using data provided by the General Social Survey (GSS).  A positive association between Internet pornography viewing and more positive extramarital sex attitudes was found.

11) Pornography and Marriage (2014) - The abstract:

We used data on 20,000 ever-married adults in the General Social Survey to examine the relationship between watching pornographic films and various measures of marital well-being. We found that adults who had watched an X-rated movie in the past year were more likely to be divorced, more likely to have had an extramarital affair, and less likely to report being happy with their marriage or happy overall. We also found that, for men, pornography use reduced the positive relationship between frequency of sex and happiness. Finally, we found that the negative relationship between pornography use and marital well-being has, if anything, grown stronger over time, during a period in which pornography has become both more explicit and more easily available.

12) More than a dalliance? Pornography consumption and extramarital sex attitudes among married U.S. adults (2014) - Excerpts:

This brief report used national panel data gathered from two separate samples of married U.S. adults. Data were gathered from the first sample in 2006 and in 2008. Data were gathered from the second sample in 2008 and in 2010. Consistent with a social learning perspective on media, prior pornography consumption was correlated with more positive subsequent extramarital sex attitudes in both samples, even after controlling for earlier extramarital sex attitudes and nine additional potential confounds.

In total, the results of the present study are consistent with the theoretical premise that pornography consumption leads to the acquisition and activation of sexual scripts, which are then used by many consumers to inform their sexual attitudes (Wright, 2013a; Wright et al., 2012a).

13) Korean Men’s Pornography use, Their Interest in Extreme Pornography, and Dyadic Sexual Relationships (2014) - Excerpt:

Six-hundred eighty-five heterosexual South Korean male college students participated in an online survey. The majority (84.5%) of respondents had viewed pornography, and for those who were sexually active (470 respondents), we found that higher interest in degrading or extreme pornography was associated with the experience of role-playing sexual scenes from pornography with a partner, and a preference for using pornography to achieve and maintain sexual excitement over having sex with a partner.

We found that higher interest in viewing degrading or extreme pornography ... has a significant positive ... association with sexual concerns.

14) Pornography and the Male Sexual Script: An Analysis of Consumption and Sexual Relations (2014) - Excerpt:

We argue pornography creates a sexual script that then guides sexual experiences. To test this, we surveyed 487 college men (ages 18-29 years) in the United States to compare their rate of pornography use with sexual preferences and concerns. Results showed the more pornography a man watches, the more likely he was to use it during sex, request particular pornographic sex acts of his partner, deliberately conjure images of pornography during sex to maintain arousal, and have concerns over his own sexual performance and body image. Further, higher pornography use was negatively associated with enjoying sexually intimate behaviors with a partner.

15) Psychological, Relational, and Sexual Correlates of Pornography Use on Young Adult Heterosexual Men in Romantic Relationships (2014) - Excerpt:

Thus, the purpose of this study was to examine theorized antecedents (i.e., gender role conflict and attachment styles) and consequences (i.e., poorer relationship quality and sexual satisfaction) of men's pornography use among 373 young adult heterosexual men. Findings revealed that both frequency of pornography use and problematic pornography use were related to greater gender role conflict, more avoidant and anxious attachment styles, poorer relationship quality, and less sexual satisfaction. In addition, the findings provided support for a theorized mediated model in which gender role conflict was linked to relational outcomes both directly and indirectly via attachment styles and pornography use.

16) Associations between relational sexual behaviour, pornography use, and pornography acceptance among US college students (2014) - Excerpt:

Using a sample of 792 emerging adults, the present study explored how the combined examination of pornography use, acceptance, and sexual behaviour within a relationship might offer insight into emerging adults' development. Results suggested clear gender differences in both pornography use and acceptance patterns. High male pornography use tended to be associated with high engagement in sex within a relationship and was associated with elevated risk-taking behaviours. High female pornography use was not associated with engagement in sexual behaviours within a relationship and was general associated with negative mental health outcomes.

17) Factors Predicting Cybersex Use and Difficulties in Forming Intimate Relationships among Male and Female Users of Cybersex (2015) - Excerpt:

This study used the Cybersex addiction test, Craving for pornography questionnaire, and a Questionnaire on intimacy among 267 participants (192 males and 75 females) mean age for males 28 and for females 25,  who were recruited from special sites that are dedicated to pornography and cybersex on the Internet. Results of regression analysis indicated that pornography, gender, and cybersex significantly predicted difficulties in intimacy and it accounted for 66.1% of the variance of rating on the intimacy questionnaire. Second, regression analysis also indicated that craving for pornography, gender, and difficulties in forming intimate relationships significantly predicted frequency of cybersex use and it accounted for 83.7% of the variance in ratings of cybersex use.

18) Male Partners’ Perceived Pornography Use and Women’s Relational and Psychological Health: The Roles of Trust, Attitudes, and Investment (2015) - Excerpt:

Results revealed that women’s reports of their male partners’ pornography use were related to less relationship satisfaction and more psychological distress. Results from the moderation analyses indicated that the direct effect of male partners’ perceived pornography use and relationship trust and the conditional indirect effects of male partners’ perceived pornography use on both relationship satisfaction and psychological distress were contingent on relationship investment. These findings indicated that when male partners’ perceived pornography use is high, women who have low or mean levels of relationship investment have less relationship trust. Finally, our results revealed that the relationship between male partners’ perceived pornography use and relational and psychological outcomes exist regardless of women’s own attitudes toward pornography

19) Relationship of love and marital satisfaction with pornography among married university students in Birjand, Iran (2015) - Excerpts:

This descriptive-correlation study was conducted on 310 married students studying at private and public universities in Birjand, in 2012-2013 academic year using random quota sampling method. It appears that pornography has a negative impact on love and marital satisfaction.

20)  From Bad to Worse? Pornography Consumption, Spousal Religiosity, Gender, and Marital Quality (2016) - Excerpts:

I test the above hypotheses using data from Wave 1 of the Portraits of American Life Study (PALS), which was fielded in 2006. PALS is a nationally representative panel survey with questions focusing on a variety of topics....Looking at bivariate correlations, for the full sample, viewing pornography is negatively associated with overall marital satisfaction, suggesting that those who view pornography more often tend to be less satisfied in their marriage than those who view pornography less often or never

21) Sexually explicit media use and relationship satisfaction a moderating role of emotional intimacy? (2016) - The authors attempted to obfuscate their findings in the abstract by stating that once sexual and relationship variables were "controlled for," they found no link between porn use and relationship satisfaction. Reality: The study found significant correlations between porn use and poorer relationship and sexual satisfaction in both males and females. Excerpt from discussion section:

For both men and women, significant, yet modest negative zero-order correlations between SEM use and relationship satisfaction were found, indicating that increased SEM use was associated with lower relationship satisfaction across gender.

22) Effect of soft core pornography on female sexuality (2016) - Excerpt:

An overall 51.6% of participants who were aware that their husbands were positive watchers reported experiencing negative emotions (depression, jealous), whereas 77% reported changes in their husbands’ attitude. Non-watchers watchers were more satisfied with their sexual life compared with their counterparts. Although watching soft-core pornography had a statistically significant effect on sexual desire, vaginal lubrication, ability to reach orgasm, and masturbation, it had no statistically significant effect on coital frequency. Watching soft-core pornography affects female sexual life by increasing sexual boredom in both men and women, causing relational difficulties.

23) A Common-Fate Analysis of Pornography Acceptance, Use, and Sexual Satisfaction Among Heterosexual Married Couples (2016) - Excerpt:

Results indicated that the shared variance of pornography acceptance was positively associated with both spouses' pornography use and that spouses' pornography use was negatively associated with their own sexual satisfaction. Wives' pornography use was found to be positively associated with the couple's shared variance of sexual satisfaction, but pornography use did not significantly mediate the relationship between pornography acceptance and sexual satisfaction.

24) Differences in Pornography Use Among Couples: Associations with Satisfaction, Stability, and Relationship Processes (2016) - Excerpt:

The present study utilized a sample of 1755 adult couples in heterosexual romantic relationships to examine how different patterns of pornography use between romantic partners may be associated with relationship outcomes. While pornography use has been generally associated with some negative and some positive couple outcomes, no study has yet explored how differences between partners may uniquely be associated with relationship well-being. Results suggested that greater discrepancies between partners in pornography use were related to less relationship satisfaction, less stability, less positive communication, and more relational aggression. Mediation analyses suggested that greater pornography use discrepancies were primarily associated with elevated levels of male relational aggression, lower female sexual desire, and less positive communication for both partners which then predicted lower relational satisfaction and stability for both partners.

25) Internet Pornography Consumption and Relationship Commitment of Filipino Married Individuals (2016) - Excerpt:

Internet pornography has many adverse effects, especially to the relationship commitment. The use of pornography directly correlates to a decrease in sexual intimacy. Hence, this might lead to weakening of the relationship of their partner. To find out the relevance of the claim, the researchers aimed to explore the relationship of Internet pornography consumption to the relationship commitment of married individuals in the Philippines. It is revealed that Internet pornography consumption has an adverse effect on the relationship commitment of married Filipino couples. Furthermore, watching porn online weakened the relationship commitment that leads to an unstable relationship. This investigation found out that internet pornography consumption has a nominal negative effect on the relationship commitment of Filipino married individuals.

26) Perceptions of relationship satisfaction and addictive behavior: Comparing pornography and marijuana use (2016) - Excerpt:

This study contributes to the broader literature on how pornography use impacts perceptions of romantic relationships. This study examined if negative outcomes due to a romantic partner’s excessive pornography use are different than negative outcomes produced by other compulsive or addictive behaviors, specifically marijuana use. This study suggests that problematic partner pornography use and problematic partner marijuana use are perceived to similarly impact romantic relationships and contribute to a decrease in relationship satisfaction.

27) The effects of sexually explicit material use on romantic relationship dynamics (2016) - Excerpts:

More specifically, couples, where no one used, reported more relationship satisfaction than those couples that had individual users. This is consistent with the previous research (Cooper et al., 1999; Manning, 2006), demonstrating that the solitary use of sexually explicit material results in negative consequences.

With gender effects held constant, individual users reported significantly less intimacy and commitment in their relationships than non-users and shared users.

Overall, how frequently someone views sexually explicit material can have an impact on users’ consequences. Our study found that high frequency users are more likely to have lower relationship satisfaction and intimacy in their romantic relationships.

28) Cyberpornography: Time Use, Perceived Addiction, Sexual Functioning, and Sexual Satisfaction (2016) - Excerpt:

First, even when controlling for perceived addiction to cyberpornography and overall sexual functioning, cyberpornography use remained directly associated with sexual dissatisfaction. Even though this negative direct association was of small magnitude, time spent viewing cyberpornography seems to be a robust predictor of lower sexual satisfaction.

29) Relationship quality predicts online sexual activities among Chinese heterosexual men and women in committed relationships (2016) - Excerpt:

In this study, we examined the online sexual activities (OSAs) of Chinese men and women in committed relationships, with a focus on the characteristics of OSAs and the factors prompting men and women with steady partners to engage in OSAs. Almost 89% of the participants reported OSA experiences in the past 12 months even when they had a real-life partner. As predicted, individuals with lower relationship quality in real life, including low relationship satisfaction, insecure attachment, and negative communication patterns, engaged in OSAs more frequently. Overall, our results suggest that variables influencing offline infidelity may also influence online infidelity.

30) The Role of Internet Pornography Use and Cyber Infidelity in the Associations between Personality, Attachment, and Couple and Sexual Satisfaction (2017) - Excerpts:

Our results indicated that pornography use is associated with couple and sexual difficulties through increased cyber infidelity.

Pornography use was negatively related to sexual satisfaction for men, but positively for women. In men, pornography use is associated with higher sexual desire, stimulation, and gratification. However, these effects may lead to decreased sexual desire their partner and decreased sexual satisfaction within the couple.

31) The Development of the Problematic Pornography Consumption Scale (PPCS) (2017) - This paper's goal was the creation of a problematic porn use questionnaire. In the process of validating the instruments, the researchers found that higher scores on the porn use questionnaire were related to lower sexual satisfaction. An excerpt:

Satisfaction with sexual life was weakly and negatively correlated with PPCS scores.

32) Explicit Sexual Movie Viewing in the United States According to Selected Marriage and Lifestyle, Work and Financial, Religion and Political Factors (2017) - Excerpts:

Analyses involved 11,372 adults who responded to questions about demographics and explicitly sexual movie use in the General Social Survey (GSS) from 2000 to 2014. Viewing such movies was related to less happiness in marriage, multiple sex partners in past year, less satisfaction with one’s financial situation, no religious preference, and a more liberal political orientation.

Explicit sexual movie viewing is associated with factors from diverse domains, including poorer relationship quality, more liberal sexual views and practices, poorer economic conditions, lower religious orientation or commitment, and more liberal political views.

33) Associative pathways between pornography consumption and reduced sexual satisfaction (2017) - Excerpt:

Guided by sexual script theory, social comparison theory, and informed by prior research on pornography, socialization, and sexual satisfaction, the present survey study of heterosexual adults tested a conceptual model linking more frequent pornography consumption to reduced sexual satisfaction via the perception that pornography is a primary source of sexual information, a preference for pornographic over partnered sexual excitement, and the devaluation of sexual communication. The model was supported by the data for both men and women.

Pornography consumption frequency was associated with perceiving pornography as a primary source of sexual information, which was associated with a preference for pornographic over partnered sexual excitement and the devaluation of sexual communication. Preferring pornographic to partnered sexual excitement and devaluing sexual communication were both associated with less sexual satisfaction.

34) The use of pornography and sexual behaviour among Norwegian men and women of differing sexual orientation (2013) - Hidden away in the study: Greater pornography use in men was correlated with lower sexual satisfaction (or "greater sexual dissatisfaction").

35)  IASR Fortieth Annual Meeting Book of Abstracts - Dubrovnik, Hrvatska, 25.-28. lipnja, 2014 - This is an abstract of a presentation given by Landripet and Stulhofer at a sexology conference. These 2 researchers published a portion of their data in this "brief communication," which is cited as finding no relationship between porn use and sexual problems. In reality, their "brief communication" doesn't mention a pretty important correlation mentioned in their paper: Only 40% of the Portuguese men used porn "frequently," while the 60% of the Norwegians used porn "frequently." The Portuguese men had far less sexual dysfunction than the Norwegians. In a shocking move, Landripet & Stulhofer omitted three other correlations between porn use and sexual problems which they presented to at the Dubrovnik conference:

However, increased pornography use was slightly but significantly associated with decreased interest for partnered sex and more prevalent sexual dysfunction among women.

Reporting a preference for specific pornographic genres were significantly associated with erectile, but not ejaculatory or desire-related male sexual dysfunction.

It's quite telling that Landripet & Stulhofer chose to omit a significant correlation between erectile dysfunction and preferences for specific genres of porn from their "brief" paper. It’s quite common for porn users to escalate into genres that do not match their original sexual tastes, and to experience ED when these conditioned porn preferences do not match real sexual encounters. As pointed out in this review of the literature (and this critique of Landripet & Stulhofer), it’s very important to assess the multiple variables associated with porn use – not just hours in the last month, or frequency in the last year.

36)  The pervasive role of sex mindset: Beliefs about the malleability of sexual life is linked to higher levels of relationship satisfaction and sexual satisfaction and lower levels of problematic pornography use (2017) - Excerpt:

The examined model showed that growth sex mindset had moderate positive association with sexual satisfaction and relationship satisfaction while problematic pornography use only showed a negative, but weak one.

37)  He’s Just Not That Into Anyone: the Impact of Sex Fantasy on Attraction (2017) This "extended abstract" discusses 4 experiments that involved fantasizing about sexual stimuli. All results suggested that sexual fantasy reduces desire for romantic relationships. Excerpt:

Engaging in sexual fantasy increases attraction to sexual targets, but decreases attraction to romantic targets. This research adds to the literature on sex fantasy, attraction, and offers practical implications on porn watching, sex in advertising, and relationships.

38) Is the Relationship Between Pornography Consumption Frequency and Lower Sexual Satisfaction Curvilinear? Results From England and Germany (2017) - Excerpts:

Several studies using different methods have found that pornography consumption is associated with lower sexual satisfaction. The language used by media-effects scholars in discussions of this association implies an expectation that lowered satisfaction is primarily due to frequent-but not infrequent-consumption. Actual analyses, however, have assumed linearity. Linear analyses presuppose that for each increase in the frequency of pornography consumption there is a correspondingly equivalent decrease in sexual satisfaction.

Survey data from two studies of heterosexual adults, one conducted in England and the other in Germany, were employed. Results were parallel in each country and were not moderated by gender. Simple slope analyses suggested that when the frequency of consumption reaches once a month, sexual satisfaction begins to decrease, and that the magnitude of the decrease becomes larger with each increase in the frequency of consumption.

39) Personal Pornography Viewing and Sexual Satisfaction: A Quadratic Analysis (2017) - Excerpts

This article presents results from a survey of approximately 1,500 U.S. adults. Quadratic analyses indicated a curvilinear relationship between personal pornography viewing and sexual satisfaction in the form of a predominately negative, concave downward curve. The nature of the curvilinearity did not differ as a function of participants' gender, relationship status, or religiosity.

For all groups, negative simple slopes were present when viewing reached once a month or more. These results are correlational only. However, if an effects perspective were adopted, they would suggest that consuming pornography less than once a month has little or no impact on satisfaction, that reductions in satisfaction tend to initiate once viewing reaches once a month, and that additional increases in the frequency of viewing lead to disproportionately larger decrements in satisfaction.

40)  The Survey of Sexual Health and Pornography among Divorce-Asking Women in West Azerbaijan-Iran: A Cross-Sectional Study (2017) - Excerpts:

One of the factors affecting the incidence of divorce and relationship problems between couples is the sexual and marital behaviors. There are several different reasons to suspect that pornography might affect divorce in either a positive or a negative way. Therefore this study evaluated the sexual health of divorce-asking in Urmia, Iran.

Conclusions: The results of the study indicated that who had low sexual satisfaction score, had higher rate of watching pornography clips. Based on current study, paying attention to family education and counseling programs especially in the sexual field will be more fruitful.

Excerpts from a 2017 review of the literature (Pornography, Pleasure, and Sexuality: Towards a Hedonic Reinforcement Model of Sexually Explicit Internet Media Use, summarizing porn's effects on sexual satisfaction:

Sexual Satisfaction

Another domain in which the present model may also have implications is sexual satisfaction. As hedonic sexual motives are often focused on obtaining sexual satisfaction, one would expect an increase in such motives to be associated with sexual satisfaction outcomes. However, given the immense number of factors that contribute to sexual satisfaction (e.g., relational intimacy, commitment, self-confidence, self-esteem), it also likely that these relationships between IPU and satisfaction will be complex. For some individuals, an increase in hedonic sexual motives may be associated with actual decreases in sexual satisfaction, as high levels of desire may be met with frustration, particularly if such increases are not met with increases in the satisfaction associated with partnered sexual activity (Santtila et al., 2007). Alternatively, if one were to start with low levels of hedonic sexual motivation, an increase in such motivation may be associated with greater sexual satisfaction as the individual becomes more focused on obtaining pleasure in a sexual encounter.

In contrast to many of the previously discussed domains related to IPU and motivations, in which research is still burgeoning, the relationships between IPU and sexual satisfaction have been extensively studied, with dozens of publications addressing the topic. Rather than exhaustively review the list of studies examining IPU and sexual satisfaction, the findings of these studies are summarized in Table 1.

In general, as indicated in Table 1, the relationships between IPU and personal sexual satisfaction are complex, but consistent with the supposition that IP may promote more hedonic sexual motivations, particularly as use increases. Among couples, there is limited support for the idea that IPU may enhance sexual satisfaction, but only when it is incorporated into partnered sexual activities. On an individual level, there is consistent evidence that IPU is predictive of lower sexual satisfaction in men, with both cross-sectional and longitudinal works pointing to the associations of such use with diminished satisfaction for men. Regarding women, scattered evidence suggests that IPU may enhance sexual satisfaction, have no effect on satisfaction, or diminish satisfaction over time. Despite these mixed findings, the conclusion of no significant effect of IPU on sexual satisfaction in women is the most common finding. These results have also been confirmed by a recent meta-analysis (Wright, Tokunaga, Kraus, & Klann, 2017). Reviewing 50 studies of pornography consumption and various satisfaction outcomes (e.g., life satisfaction, personal satisfaction, relational satisfaction, sexual satisfaction), this meta-analysis found that pornography consumption (not internet-specific) was consistently related to and predictive of lower interpersonal satisfaction variables, including sexual satisfaction, but for men only. No significant findings were found for women. Collectively, such mixed results preclude definitive conclusions about the role of IP in influencing satisfaction for women.

One of the most important findings of recent works examining IPU and sexual satisfaction is that there appears to be a curvilinear relationship between use and satisfaction, so that satisfaction decreases more sharply as IPU becomes more common (e.g., Wright, Steffen, & Sun, 2017; Wright, Brigdes, Sun, Ezzell, & Johnson, 2017). The details of these studies are reflected in Table 1. Given clear evidence across multiple international samples, it seems reasonable to accept the conclusion that as IPU increases to more than once per month, sexual satisfaction decreases. Furthermore, although these studies (Wright, Steffen, et al., 2017; Wright, Bridges et al., 2017) were cross-sectional, given the number of longitudinal studies (e.g., Peter & Valkenburg, 2009) linking IPU to lower sexual satisfaction, it is reasonable to infer that these associations are causal in nature. As IPU increases, interpersonal sexual satisfaction appears to decrease, which is consistent with the present model’s contention that IPU is associated with more hedonic and self-focused sexual motivation.

Finally, this anomalous 2016 study is often cited by Nicole Prause and her colleague David Ley as evidence that porn use offers nothing but benefits to couples: Perceived Effects of Pornography on the Couple Relationship: Initial Findings of Open-Ended, Participant-Informed, "Bottom-Up" Research. (2016).

Two glaring methodical flaws produce meaningless results:

  1. The study does not rest on a representative sample. Whereas most studies show that a tiny minority of porn users' female partners use porn, in this study 95% of the women used porn on their own. And 85% of the women had used porn since the beginning of the relationship (in some cases for years). Those rates are higher than in college-aged men! In other words, the researchers appear to have skewed their sample to produce the results they were seeking. Reality: Cross-sectional data from the largest US survey (General Social Survey) reported that only 2.6% of women had visited a "pornographic website" in the last month. Data from 2000, 2002, 2004. For more see - Pornography and Marriage (2014)
  1. The study used "open ended" questions where the subject could ramble on and on about porn. Then the researchers read the ramblings and decided, after the fact, what answers were "important," and how to present (spin?) them in their paper. Then the researchers then had the gall to suggest that all the other studies on porn and relationships, which employed more established, scientific methodology and straightforward questions about porn's effects, were flawed. How is this method justified?

Despite these fatal flaws several couples reported significant negative effects from porn use, such as:

  • Pornography is easier, more interesting, more arousing, more desirable, or more gratifying than sex with a partner
  • Pornography use is desensitizing, decreases the ability to achieve or maintain sexual arousal, or to achieve orgasm.
  • Some said that specifically described desensitization as the effect of pornography use
  • Some were concerned a loss of intimacy or love.
  • It was suggested that pornography makes real sex more boring, more routine, less exiting, or less enjoyable

For some reason these negative effects did not appear in articles about the study. The lead author's new website and his attempt at fundraising raise questions.


SLIDE 34
 

“I feel like the next Sir Isaac Newton or Leonardo da Vinci!

Since I quit a month ago, I've literally: started a business, taken up piano, been studying French every day, been programming, drawing, writing, started managing my finances, and have more awesome ideas than I know what to do with. My confidence is sky high. I already feel like I can talk to any girl. I’m the same guy who took 2 and a 1/2 extra years to graduate from college - because of procrastination and depression.”

ORIGINAL SUPPORT:

This is an anecdote. However, I had seen hundreds just like it by the time I did The Great Porn Experiment. Empirical support for "arousal addiction" (internet porn, internet gaming) inducing or exacerbating mental and emotional conditions, along with cognitive problems, was provided on Slide 11. See Slide 21 for links to forums were men eliminated porn and described remission of similar symptoms.

See the following articles (and the comments sections below the articles) for additional self-reports similar to this one

UPDATED SUPPORT:

Empirical and clinical support for "arousal addiction" (internet porn, internet gaming) inducing or exacerbating mental and emotional conditions was provided on Slide 11.

As already noted hundreds of articles have been published since 2011 that describe an unprecedented rise in adolescent mental health problems (depression, anxiety, social anxiety). Many of the experts quoted in the articles cite internet use and widespread adoption of smartphones as the primary reason for the increase in mental health problems.


SLIDE 35

I'll conclude with a wish: I'd like to see Zimbardo's guys who are wiping out, and their caregivers, listen to the thousands of men who are teaching us about arousal addiction -- by escaping it.

Thanks for listening.

ORIGINAL & UPDATED SUPPORT:

Since The Great Porn Experiment was a direct response to Philip Zimbardo's "Demise of Guys" TED talk, I employed the same terminology as Zimbardo (“Arousal addiction“) to describe compulsive internet use (video gaming, viewing porn) by young men. Both the original and updated support for the existence of internet addiction and internet pornography addiction have been provided on Slides 12, 17, 18, 19 and 20.

 


The first page contains slides 1 through 17