How to recognize biased articles: They cite Prause et al., 2015 (falsely claiming it debunks porn addiction), while omitting over 50 neurological studies supporting porn addiction

Introduction

A number of articles and interviews have attempted to push-back at the TIME article (“Porn and the Threat to Virility”) and the Utah resolution declaring internet porn a public health problem. What might be a few “dead giveaways” that such an article is nothing more than a propaganda piece?

  1. Psychologists David Ley and/or Nicole Prause are cited as “the experts,” while actual top addiction neuroscientists, who have published highly respected studies on porn users (Voon, Kraus, Potenza, Brand, Laier, Hajela, Kuhn, Gallinat, Klucken, Seok, Sohn, Gola, Banca, etc.), are omitted. Neither Ley nor Prause are affiliated with any university, yet some journalists, perhaps influenced by Prause’s potent media services, mysteriously prefer both over the top neuroscientists at Yale University, Cambridge University, University of Duisburg-Essen, and the Max Planck Institute. Go figure.
  2. The articles tend to cite Prause’s lone, anomalous 2015 EEG study (Prause et al., 2015) as proof that porn addiction doesn’t exist, while simultaneously omitting 54 other neurological studies and 31 recent reviews of the literature & commentaries: Current list of brain studies on porn users/sex addicts. (a few articles cite Prause’s 2013 EEG study (Steele et al.), which, in fact, lends support to the porn addiction model and porn-induced sexual conditioning).
  3. The articles omit 31 recent literature reviews & commentaries by some of the top neuroscientists in the world. All support the addiction model.
  4. The articles omit any mention of  WHO’s ICD-11), which contains a new diagnosis suitable for porn addiction: “Compulsive Sexual Behavior Disorder.”
  5. The articles omit over 60 studies pointing to escalation & habituation in porn users (and even withdrawal symptoms).
  6. The articles omit all 14 studies reporting withdrawal symptoms in porn users.
  7. The articles omit over 40 studies linking porn use to sexual problems and lower arousal to sexual stimuli (the first 7 studies in the list demonstrate causation, as participants eliminated porn use and healed chronic sexual dysfunctions).
  8. The articles omit over 80 studies linking porn use to less sexual satisfaction and poorer intimate relationships.
  9. The articles omit over 85 studies linking porn use to poorer mental-emotional health & poorer cognitive outcomes.
  10. The articles omit over 40 studies linking porn use to “un-egalitarian attitudes” toward women
  11. The articles omit the 280 studies on adolescents, which report that porn use is related to such factors as poorer academics, more sexist attitudes, more aggression, poorer health, poorer relationships, lower life satisfaction, viewing people as objects, increased sexual risk taking, less condom use, greater sexual violence, unexplained anxiety, greater sexual coercion, less sexual satisfaction, lower libido, greater permissive attitudes, and a whole lot more.
  12. The articles falsely claim that porn addicts simply have a high libido, even though over 25 studies have falsified this often repeated meme.
  13. In classic “astroturfing-style,” the articles engage in ad hominem attacks on those with opposing views (such as libelous claims of nonexistent “restraining-orders,” “stalking,” and religious and profit motives), without supplying objective proof of such claims.

Update: In this 2018 presentation Gary Wilson exposes the truth behind 5 questionable and misleading studies, including the two Nicole Prause EEG studies (Steele et al., 2013 and Prause et al., 2015): Porn Research: Fact or Fiction?


Reality Check Concerning Prause’s 2015 EEG Study (Prause et al., 2015)

Prause’s 2015 EEG study (claiming to debunk porn addiction) actually supports the existence of porn addiction because her team found desensitization in the heavy porn users.

Compared to controls, more frequent porn users had lower brain activation to one-second exposure to photos of vanilla porn. The lead author, Nicole Prause claims these results debunk porn addiction. However, these findings align perfectly with Kühn & Gallinat (2014), which found that more porn use correlated with lower brain activation in response to pictures of vanilla porn (and less gray matter in the dorsal striatum). In other words, the frequent porn users were desensitized to still images and needed greater stimulation than occasional porn users. 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. 10 peer-reviewed papers agree with the YBOP analysis, namely that what Prause actually found is consistent with the effects of addiction in her study’s subjects:

  1. Neuroscience of Internet Pornography Addiction: A Review and Update (2015)
  2. Decreased LPP for sexual images in problematic pornography users may be consistent with addiction models. Everything depends on the model (2016)
  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)
  7. Neurocognitive mechanisms in compulsive sexual behavior disorder (2018)
  8. Online Porn Addiction: What We Know and What We Don’t—A Systematic Review (2019)
  9. The Initiation and Development of Cybersex Addiction: Individual Vulnerability, Reinforcement Mechanism and Neural Mechanism (2019)
  10. Do Varying Levels of Exposure to Pornography and Violence Have an Effect on Non-Conscious Emotion in Men (2020)

Author of the second 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.”

What legitimate researcher would ever claim to have debunked an entire field of research and to refute all previous studies with a single EEG study? (Close ties to the industry in question might cloud a researcher’s perceptions).

Not only was the title scientifically unjustified, Nicole Prause claimed her study contained 122 subjects (N). In reality, the study had only 55 subjects who were “experiencing problems regulating their viewing of sexual images”. The subjects were recruited from Pocatello Idaho, which is over 50% Mormon. The other 67 participants were controls.

In a second dubious claim, Prause et al., 2015 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.

In a third claim Nicole Prause has consistently asserted that Prause et al., 2015 is “the largest neuroscience investigation of porn addiction ever conducted”. It should be noted that compared to brain scan studies, EEG studies are far less expensive per subject. It’s easy to gather a large group of “porn addicted” subjects if you don’t screen the subjects for porn addiction or any exclusionary condition (mental problems, addictions, psychotropic drug use, etc.). A few problems with Prause’s claim:

  1. It’s not a study on porn addiction if it has no porn addicts. This study, and 2 earlier Prause studies (Prause et al., 2013 & Steele et al., 2013), did not assess whether any of the subjects were porn addicts or not. Prause admitted in an interview that many of the subjects had little difficulty controlling use: they were not addicts. All of the subjects would have to have been confirmed porn addicts to permit a legitimate comparison with a group of non-porn addicts. In addition the Prause Studies did not screen subjects for mental disorders, compulsive behaviors, or other addictions. Four of the ten peer-reviewed critiques point out these fatal flaws: 2, 3, 4, 8.
  2. “HPA axis dysregulation in men with hypersexual disorder” (2015) could be considered the largest neuroscience-based study to date on “hypersexuals” (with 67 subjects in treatment for sex addiction, as compared to Prause’s 55 subjects who were upset about their porn use). The study assessed the brain’s response to stress by assessing a hormone release by the brain (ACTH), and a hormone controlled by the brain (cortisol). While this study was a published a few months after Prause et al., 2015, Nicole Prause continues to claim her EEG study as the largest.
  3. Brain Structure and Functional Connectivity Associated With Pornography Consumption: The Brain on Porn (2014) – Could be considered larger than Prause et al., 2015, because it had 64 subjects, and all were carefully screened for exclusionary items such as addictions, substance use, mental disorders, and medical & neurological disorders. The 3 Prause Studies did not do this.

You Can’t “Debunk Porn Addiction” if Your Subjects Are Not Porn Addicts

The 3 Prause Studies (Prause et al., 2013, Prause et al., 2015, Steele et al., 2013.) all involved the same subjects. Here’s what we know about the “porn addicted users” in Prause’s 3 studies (the “Prause Studies”): They were not necessarily addicts, as they were never assessed for porn addiction. Thus, they can’t legitimately be used to “falsify” anything to do with the addiction model. As a group they 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 “porn addicted” subjects:

  1. Prause et al., 2013: “Porn addicted users” reported more boredom and distraction while viewing vanilla porn.
  2. 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.
  3. Prause et al., 2015: “Porn addicted 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 three studies: The more frequent 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.

Make no mistake, neither Steele et al., 2013 nor Prause et al., 2015 described these 55 subjects as porn addicts or compulsive porn users. The subjects only admitted to feeling “distressed” by their porn use. 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.”

Besides not establishing which of the subjects were porn addicted, the Prause Studies did not screen subjects for mental disorders, compulsive behaviors, current drug use, or other addictions. This is critically important for any “brain study” on addiction, lest confounds render results meaningless.

In summary, the 3 Prause Studies did not assess whether the subjects were porn addicts or not. The authors admitted that many of the subjects had little difficulty controlling use. All of the subjects would have to have been confirmed porn addicts to permit a legitimate comparison with a group of non-porn addicts.

In 2013 Prause Said That Less Brain Activation Would Indicate Habituation or Addiction

You read that correctly. Prause’s 2015 claim of “debunking porn addiction” represents a flip-flop from her 2013 study’s claim of “debunking porn addiction.”

In her 2013 EEG study and related blog post, Prause admits that reduced brain activation would indicate habituation or addiction, but claimed her subjects didn’t show reduced activation. This claim, however, was groundless as explained here. She had no control group, so she could not compare “porn addicts'” EEG readings to “non-addicts'” readings. As a result, her 2013 study told us nothing about the EEG readings for either healthy individuals or “hypersexuals.”

Finally, in 2015 she added control subjects and published a second study. Sure enough, her “porn addicted” subjects displayed reduced brain activation in comparison to controls – just as would be expected in porn users suffering from habituation or addiction. Undaunted by findings that undermined her 2013 conclusion, she boldly, and without any basis in science, claimed that her corrected findings – which were consistent with the presence of addiction – “dismantled porn addiction.” And this is the talking point these propaganda pieces latch onto, with no support other than Prause’s unfounded claims.

Let’s back up and look more closely at Prause’s views from her 2013 study (Steele et al.):

“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 VSS.

In 2013, Prause said that porn addicts, when compared to controls, could either 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 her 2013 EEG study was published, Prause and David Ley teamed up to write this Psychology Today blog post about her upcoming 2013 study (and its unsupported claims). In it they admit 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. Later, however, in 2015, when Prause added controls for comparison and found evidence of desensitization (common in addicts), she tells 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 executed a complete flip-flop. In 2015, she claimed the evidence of desensitization that she found when she added the control group isn’t evidence of addiction (which she claimed in 2013 it would have been). Instead, evidence of desensitization now (magically) “disproves addiction” (even though it aligns with addiction perfectly). This is inconsistent and unscientific, and suggests that regardless of opposing findings, she will always claim to have “disproven addiction.”

What About Brain Studies That Debunk Porn Addiction?

There are none. 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). 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 studies just discussed). However, whenever an article claiming to debunk porn addiction cites a study, I expect you will find one of her two EEG studies, or an irresponsible “review” by Prause, Ley and Finn. Here they are for easy reference:

  1. Sexual Desire, not Hypersexuality, is Related to Neurophysiological Responses Elicited by Sexual Images (Steele et al., 2013)
  2. Modulation of Late Positive Potentials by Sexual Images in Problem Users and Controls Inconsistent with “Porn Addiction” (Prause et al., 2015)
  3. The Emperor Has No Clothes: A Review of the ‘Pornography Addiction’ Model, by David Ley, Nicole Prause & Peter Finn (Ley et al., 2014)

Kinsey Institute grad Nicole Prause is the lead author on studies 1 and 2, and is the second author on paper #3. We already saw above that study #2 (Prause et al., 2015) lends support to the porn addiction model. But how does Prause’s 2013 EEG study (Steele et al., 2013), touted in the media as evidence against the existence of porn addiction, actually support the porn addiction model?

This study’s only significant finding was that individuals with greater cue-reactivity to porn had less desire for sex with a partner (but not lower desire to masturbate to porn). Put another way, individuals with more brain activation and cravings for porn would rather masturbate to porn than have sex with a real person. This is typical of addicts, not healthy subjects.

Study spokesman Nicole Prause claimed that frequent porn users merely had high libido, yet the results of the study say something quite different. As Valerie Voon (and 10 other neuroscientists) explained, Prause’s 2013 findings of greater cue-reactivity to porn coupled with lower desire for sex with real partners aligned with their 2014 brain scan study on porn addicts. Put simply, the actual findings of the 2013 EEG study in no way match the unsupported “debunking” headlines. 8 peer-reviewed papers expose the truth about this earlier study by Prause’s team: Peer-reviewed critiques of Steele et al., 2013. (Also see this extensive YBOP critique.)

As a side note, this same 2013 study reported higher EEG readings (P300) when subjects were exposed to porn photos. Studies consistently show that an elevated P300 occurs when addicts are exposed to cues (such as images) related to their addiction. This finding supports the porn addiction model, as the above peer-reviewed papers explained and psychology professor emeritus John A. Johnson pointed out in a comment under a 2013 Psychology Today Prause interview:

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 has no opinion on sex or porn 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.”

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…..

Aside from the many unsupported claims in the press, it’s disturbing that Prause’s 2013 EGG study passed peer-review, as it suffered from serious methodological flaws:

  1. subjects were heterogeneous (males, females, non-heterosexuals);
  2. subjects were not screened for mental disorders or addictions;
  3. study had no control group for comparison;
  4. questionnaires were not validated for porn addiction.

The third paper listed above is not a study at all. Instead, it poses as an impartial “review of the literature” on porn addiction and porn’s effects. Nothing could be farther from the truth. The lead author, David Ley, is the author of The Myth of Sex Addiction and Nicole Prause is the second author. Ley & Prause not only teamed up to write paper #3, they also teamed up to write a Psychology Today blog post about paper #1. The blog post appeared 5 months before Prause’s paper was formally published (so no one could refute it). You may have seen Ley’s blog post with the oh-so-catchy title: “Your Brain on Porn – It’s NOT Addictive”. Ley zealously denies both sex and porn addiction. He has written 20 or so blog posts attacking porn-recovery forums, and dismissing porn addiction and porn-induced ED. He is not a scientist, but rather a clinical psychologist, and like Prause is not employed with any university or research institute. Read more about Ley & Prause and their collaborations here.

The following is a very long analysis of paper #3, which goes line-by-line, showing all the shenanigans Ley & Prause incorporated in their “review”: The Emperor Has No Clothes: A Fractured Fairytale Posing As A Review. It completely dismantles the so-called review, and documents dozens of misrepresentations of the research they cited. The most shocking aspect of the Ley review is that it omitted ALL the many studies that reported negative effects related to porn use or found porn addiction!

Yes, you read that right. While purporting to write an “objective” review, Ley & Prause justified omitting hundreds of studies on the grounds that these were correlational studies. Guess what? Virtually all studies on porn are correlational, even those they cited, or misused. There are, and pretty much will be, only correlational studies, because researchers have no way to prove causation by comparing users with “porn virgins” or by keeping subjects off of porn for extended periods in order compare effects. (Thousands of guys are quitting porn voluntarily on various forums, however, and their results suggest that removing internet porn is the key variable in their symptoms and recoveries.)

Inherent Bias and Conflicts of Interest

It’s unprecedented for a legitimate researcher to claim that their lone anomalous study has debunked a hypothesis supported by multiple neurological studies and decades of relevant research. Moreover, what legitimate researcher would be constantly tweeting that their lone paper has debunked porn addiction? What legitimate researcher would personally attack young men who run porn-recovery forums? What legitimate sex researcher would vociferously (and viciously) campaign against proposition 60 (condoms in porn)? What legitimate sex researcher would have her photo (far right) taken on the red carpet of the X-Rated Critics Organization (XRCO) awards ceremony, arm in arm with porn stars & producers?. (According to Wikipedia the XRCO Awards are given by the American X-Rated Critics Organization annually to people working in adult entertainment and it is the only adult industry awards show reserved exclusively for industry members.[1]) For much more documentation of Prause’s intimate relationship with the porn industry, see: Is Nicole Prause Influenced by the Porn Industry?.

What’s going on here? Quite a bit as this page documents the tip of the iceberg concerning Prause’s harassment and cyberstalking of anyone who suggests porn might cause a problem. By her own admission, rejects the concept of porn addiction. For example, a quote from this recent Martin Daubney article about sex/porn addictions:

Dr Nicole Prause, principal investigator at the Sexual Psychophysiology and Affective Neuroscience (Span) Laboratory in Los Angeles, calls herself a “professional debunker” of sex addiction.

In addition, Nicole Prause’s former Twitter slogan suggests she may lack the impartiality required for scientific research:

“Studying why people choose to engage in sexual behaviors without invoking addiction nonsense”

Updates on Nicole Prause’s twitter slogan:

  1. UCLA did not renew Prause’s contract. She hasn’t been employed by any university since early 2015.
  2. In October, 2015 Prause’s original Twitter account is permanently suspended for harassment.

While many articles continue to describe Prause as a UCLA researcher, she hasn’t been employed by any university since the beginning of 2015. Finally, it’s important to know that the enterprising Prause offered (for a fee) her “expert” testimony against sex addiction and porn addiction. It seems as though Prause is attempting to sell her services to profit from the unsupportable anti-porn addiction conclusions of her two EEG studies (1, 2), even though 18 peer-reviewed analyses say both studies support the addiction model!

Paid by the porn industry. In a blatant financial conflict of interest, David Ley is being compensated by porn industry giant X-hamster to promote their websites and to convince users that porn addiction and sex addiction are myths!  Specifically, David Ley and the newly formed Sexual Health Alliance (SHA) have partnered with a X-Hamster website (Strip-Chat). See “Stripchat aligns with Sexual Health Alliance to stroke your anxious porn-centric brain“:

The fledgling Sexual health Alliance (SHA) advisory board includes David Ley and two other RealYourBrainOnPorn.com “experts” (Justin Lehmiller & Chris Donahue). RealYBOP is a group of openly pro-porn, self-proclaimed “experts” headed by Nicole Prause. This group is currently engaged in illegal trademark infringement and squatting directed toward the legitimate YBOP. Put simply, those trying to silence YBOP are also being paid by the porn industry to promote its/their businesses, and assure users that porn and cam sites cause no problems (note: Nicole Prause has close, public ties to the porn industry as thoroughly documented on this page).

In this article, Ley dismisses his compensated promotion of the porn industry:

Granted, sexual health professionals partnering directly with commercial porn platforms face some potential downsides, particularly for those who’d like to present themselves as completely unbiased. “I fully anticipate [anti-porn advocates] to all scream, ‘Oh, look, see, David Ley is working for porn,’” says Ley, whose name is routinely mentioned with disdain in anti-masturbation communities like NoFap.

But even if his work with Stripchat will undoubtedly provide fodder to anyone eager to write him off as biased or in the pocket of the porn lobby, for Ley, that tradeoff is worth it. “If we want to help [anxious porn consumers], we have to go to them,” he says. “And this is how we do that.”

Biased? Ley reminds us of the infamous tobacco doctors, and the Sexual health Alliance, the Tobacco Institute.

In addition, David Ley is being paid to debunk porn and sex addiction. At the end of this Psychology Today blog post Ley states:

“Disclosure: David Ley has provided testimony in legal cases involving claims of sex addiction.”

In 2019 David Ley’s new website offered his well-compensated “debunking” services:

David J. Ley, Ph.D., is a clinical psychologist and AASECT-certified supervisor of sex therapy, based in Albuquerque, NM. He has provided expert witness and forensic testimony in a number of cases around the United States. Dr. Ley is regarded as an expert in debunking claims of sexual addiction, and has been certified as an expert witness on this topic. He has testified in state and federal courts.

Contact him to obtain his fee schedule and arrange an appointment to discuss your interest.

Ley also profits from selling two books that deny sex and porn addiction (“The Myth of Sex Addiction,” 2012 and “Ethical Porn for Dicks,” 2016). Pornhub (which is owned by porn giant MindGeek) is one of the five back-cover endorsements listed for Ley’s 2016 book about porn:

Note: PornHub was the second Twitter account to retweet RealYBOP’s initial tweet announcing its “expert” website, suggesting a coordinated effort between PornHub and the RealYBOP experts. Wow!

Finally, David Ley makes money via CEU seminars, where he promotes the addiction-deniers’ ideology set forth in his two books (which recklessly ignores hundreds of studies and the significance of the new Compulsive Sexual Behavior Disorder diagnosis in the World Health Organization’s diagnostic manual). Ley is compensated for his many talks featuring his biased views of porn. In this 2019 presentation Ley appears to support and promote adolescent porn use: Developing Positive Sexuality and Responsible Pornography Use in Adolescents.

The above is just the tip of the Prause and Ley iceberg.

Dismantling The Naysayers’ Talking Points

If you want a quick refutation of the naysayers’ pseudoscientific claims that they have “dismantled porn addiction,” watch Gabe Deem’s video: PORN MYTHS – The Truth Behind Addiction And Sexual Dysfunctions.

The following articles cite numerous studies, furnish illustrative examples, and elaborate logical arguments to dismantle many common anti-porn addiction propaganda talking points:

This section collects studies about which YBOP and others have reservations – Questionable & Misleading Studies. In some, the methodology raises concerns. In others, the conclusions appear inadequately supported. In others, the title or terminology used is misleading given the actual study results. Some grossly misrepresent the actual findings.

All the Neuroscience Supports the Porn Addiction Model

Listed below are all the studies assessing the brain structure and functioning of Internet porn users (even the one claiming to have debunked porn addiction). To date every study offers support for the porn addiction model. The results of these 53 studies (and upcoming studies) are consistent with 370+ Internet addiction brain studies, many of which also include internet porn use. To date every study offers support for the porn addiction model (no studies falsify the porn addiction model), as do 29 recent neuroscience-based reviews of the literature:

  1. Neuroscience of Internet Pornography Addiction: A Review and Update (2015). The review also critiques two recent headline-grabbing EEG studies which purport to have “debunked” porn addiction.
  2. Sex Addiction as a Disease: Evidence for Assessment, Diagnosis, and Response to Critics (2015), which provides a chart that takes on specific criticisms and offers citations that counter them.
  3. Neurobiology of Compulsive Sexual Behavior: Emerging Science (2016) Excerpt: “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.”
  4. Should Compulsive Sexual Behavior be Considered an Addiction? (2016) Excerpt: “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”
  5. Neurobiological Basis of Hypersexuality (2016). Excerpt: “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.
  6. Compulsive Sexual Behaviour as a Behavioural Addiction: The Impact of the Internet and Other Issues (2016)  Excerpts: “more emphasis is needed on the characteristics of the internet as these may facilitate problematic sexual behaviour.” and “clinical evidence from those who help and treat such individuals should be given greater credence by the psychiatric community.”
  7. Cybersex Addiction (2015) Excerpts: 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. Neuroimaging studies support the assumption of meaningful commonalities between cybersex addiction and other behavioral addictions as well as substance dependency.
  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 from DSM-5, a diagnosis of CSB (excessive sex drive) can be made using ICD-10. CSB is also being considered by ICD-11.
  9. 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 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 provide 3 clinical reports of men who developed porn-induced sexual dysfunctions.
  10. 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.
  11. Sexual Addiction chapter from Neurobiology of Addictions, Oxford Press (2016) – Excerpt: 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.
  12. Neuroscientific Approaches to Online Pornography Addiction (2017) – Excerpt: 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.
  13. Is excessive sexual behaviour an addictive disorder? (2017) – Excerpts: 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. 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.
  14. The Proof of the Pudding Is in the Tasting: Data Are Needed to Test Models and Hypotheses Related to Compulsive Sexual Behaviors (2018) – Excerpts: Among the domains that may suggest similarities between CSB and addictive disorders are neuroimaging studies, with several recent studies omitted by Walton et al. (2017). Initial studies often examined CSB with respect to models of addiction (reviewed in Gola, Wordecha, Marchewka, & Sescousse, 2016b; Kraus, Voon, & Potenza, 2016b).
  15. Promoting educational, classification, treatment, and policy initiatives Commentary on: Compulsive sexual behaviour disorder in the ICD-11 (Kraus et al., 2018) – Excerpts: The current proposal of classifying CSB disorder as an impulse-control disorder is controversial as alternate models have been proposed (Kor, Fogel, Reid, & Potenza, 2013). There are data suggesting that CSB shares many features with addictions (Kraus et al., 2016), including recent data indicating increased reactivity of reward-related brain regions in response to cues associated with erotic stimuli (Brand, Snagowski, Laier, & Maderwald, 2016; Gola, Wordecha, Marchewka, & Sescousse, 2016; Gola et al., 2017; Klucken, Wehrum-Osinsky, Schweckendiek, Kruse, & Stark, 2016; Voon et al., 2014.
  16. Compulsive Sexual Behavior in Humans and Preclinical Models (2018) – Excerpts: Compulsive sexual behavior (CSB) is widely regarded as a “behavioral addiction,” and is a major threat to quality of life and both physical and mental health. In conclusion, this review summarized the behavioral and neuroimaging studies on human CSB and comorbidity with other disorders, including substance abuse. Together, these studies indicate that CSB is associated with functional alterations in dorsal anterior cingulate and prefrontal cortex, amygdala, striatum, and thalamus, in addition to decreased connectivity between amygdala and prefrontal cortex.
  17. Sexual Dysfunctions in the Internet Era (2018) – Excerpt: Among behavioral addictions, problematic Internet use and online pornography consumption are often cited as possible risk factors for sexual dysfunction, often with no definite boundary between the two phenomena. Online users are attracted to Internet pornography because of its anonymity, affordability, and accessibility, and in many cases its usage could lead users through a cybersex addiction: in these cases, users are more likely to forget the “evolutionary” role of sex, finding more excitement in self-selected sexually explicit material than in intercourse.
  18. Neurocognitive mechanisms in compulsive sexual behavior disorder (2018) – Excerpt: To date, most neuroimaging research on compulsive sexual behavior has provided evidence of overlapping mechanisms underlying compulsive sexual behavior and non-sexual addictions. Compulsive sexual behavior is associated with altered functioning in brain regions and networks implicated in sensitization, habituation, impulse dyscontrol, and reward processing in patterns like substance, gambling, and gaming addictions. Key brain regions linked to CSB features include the frontal and temporal cortices, amygdala, and striatum, including the nucleus accumbens.
  19. A Current Understanding of the Behavioral Neuroscience of Compulsive Sexual Behavior Disorder and Problematic Pornography Use – Excerpt: Recent neurobiological studies have revealed that compulsive sexual behaviors are associated with altered processing of sexual material and differences in brain structure and function. Although few neurobiological studies of CSBD have been conducted to date, existing data suggest neurobiological abnormalities share communalities with other additions such as substance use and gambling disorders. Thus, existing data suggest that its classification may be better suited as a behavioral addiction rather than an impulse-control disorder.
  20. Ventral Striatal Reactivity in Compulsive Sexual Behaviors (2018) – Excerpt: Among currently available studies, we were able to find nine publications (Table 1) which utilized functional magnetic resonance imaging. Only four of these (3639) directly investigated processing of erotic cues and/or rewards and reported findings related to ventral striatum activations. Three studies indicate increased ventral striatal reactivity for erotic stimuli (3639) or cues predicting such stimuli (3639). These findings are consistent with Incentive Salience Theory (IST) (28), one of the most prominent frameworks describing brain functioning in addiction.
  21. Online Porn Addiction: What We Know and What We Don’t—A Systematic Review (2019) – Excerpt: As far as we know, a number of recent studies support this entity as an addiction with important clinical manifestations such as sexual dysfunction and psychosexual dissatisfaction. Most of the existing work is based off on similar research done on substance addicts, based on the hypothesis of online pornography as a ‘supranormal stimulus’ akin to an actual substance that, through continued consumption, can spark an addictive disorder.
  22. Occurrence and development of online porn addiction: individual susceptibility factors, strengthening mechanisms and neural mechanisms (2019) – Excerpt: The long-term experience of online pornography has led to the sensitization of such people to online pornography-related clues, which has led to a growing sense of craving, compulsive use of online pornography under the dual factors of temptation and functional impairment. The sense of satisfaction gained from it is getting weaker and weaker, so more and more online pornography is needed to maintain the previous emotional state and become addicted.
  23. Theories, prevention, and treatment of pornography-use disorder (2019) – Excerpt: Compulsive sexual behavior disorder, including problematic pornography use, has been included in the ICD-11 as impulse control disorder. The diagnostic criteria for this disorder, however, are very similar to the criteria for disorders due to addictive behaviors… Theoretical considerations and empirical evidence suggest that the psychological and neurobiological mechanisms involved in addictive disorders are also valid for pornography-use disorder.
  24. Self-perceived Problematic Pornography Use: An Integrative Model from a Research Domain Criteria and Ecological Perspective (2019) – Excerpt: Self-perceived problematic pornography use seems to be related to multiple units of analysis and different systems in the organism. Based on the findings within the RDoC paradigm described above, it is possible to create a cohesive model in which different units of analysis impact each other (Fig. 1). These changes in internal and behavioral mechanisms among people with SPPPU are similar to those observed in people with substance addictions, and map into models of addiction.
  25. Cybersex addiction: an overview of the development and treatment of a newly emerging disorder (2020) – Excerpts: Cybersex addiction is a non-substance related addiction that involves online sexual activity on the internet. Nowadays, various kinds of things related to sex or pornography are easily accessible through internet media. In Indonesia, sexuality is usually assumed taboo but most young people have been exposed to pornography. It can lead to an addiction with many negative effects on users, such as relationships, money, and psychiatric problems like major depression and anxiety disorders.
  26. Which Conditions Should Be Considered as Disorders in the International Classification of Diseases (ICD-11) Designation of “Other Specified Disorders Due to Addictive Behaviors”? (2020) – Excerpts: Data from self-report, behavioral, electrophysiological, and neuroimaging studies demonstrate an involvement of psychological processes and underlying neural correlates that have been investigated and established to varying degrees for substance-use disorders and gambling/gaming disorders (criterion 3). Commonalities noted in prior studies include cue-reactivity and craving accompanied by increased activity in reward-related brain areas, attentional biases, disadvantageous decision-making, and (stimuli-specific) inhibitory control.
  27. The Addictive Nature of Compulsive Sexual Behaviours and Problematic Online Pornography Consumption: A Review – Excerpts: Available findings suggest that there are several features of CSBD and POPU that are consistent with characteristics of addiction, and that interventions helpful in targeting behavioural and substance addictions warrant consideration for adaptation and use in supporting individuals with CSBD and POPU….  The neurobiology of POPU and CSBD involves a number of shared neuroanatomical correlates with established substance use disorders, similar neuropsychological mechanisms, as well as common neurophysiological alterations in the dopamine reward system.
  28. Dysfunctional sexual behaviors: definition, clinical contexts, neurobiological profiles and treatments (2020) – Excerpts: Porn addiction, although distinct neurobiologically from sexual addiction, is still a form of behavioral addiction….The sudden suspension of porn addiction causes negative effects in mood, excitement, and relational and sexual satisfaction….The massive use of pornography facilitates the onset of psychosocial disorders and relationship difficulties…
  29. What should be included in the criteria for compulsive sexual behavior disorder? (2020) – Excerpts: The classification of CSBD as an impulse control disorder also warrants consideration. … Additional research may help refine the most appropriate classification of CSBD as happened with gambling disorder, reclassified from the category of impulse control disorders to non-substance or behavioral addictions in DSM-5 and ICD-11. … impulsivity may not contribute as strongly to problematic pornography use as some have proposed (Bőthe et al., 2019).
  30. Decision-Making in Gambling Disorder, Problematic Pornography Use, and Binge-Eating Disorder: Similarities and Differences (2021) – Excerpts: Similarities between CSBD and addictions have been described, and impaired control, persistent use despite adverse consequences, and tendencies to engage in risky decisions may be shared features (37••, 40). Individuals with these disorders often show impaired cognitive control and disadvantageous decision-making [12, 15,16,17]. Deficits in decision-making processes and goal-directed learning have been found across multiple disorders.

See Questionable & Misleading Studies for highly publicized papers that are not what they claim to be.

See this page for numerous studies linking porn use to sexual problems and decreased sexual & relationship satisfaction

“Brain Studies” (fMRI, MRI, EEG, Neuro-endocrine):

  1. Brain Structure and Functional Connectivity Associated With Pornography Consumption: The Brain on Porn (2014) – This Max Planck Institute fMRI study found less gray 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 believed their findings indicated desensitization, and possibly tolerance, which is the need for greater stimulation to achieve the same high. The study also reported that more porn viewing was linked to poorer connections between the reward circuit and prefrontal cortex.
  2. Neural Correlates of Sexual Cue Reactivity in Individuals with and without Compulsive Sexual Behaviours (2014) – The first in a series of Cambridge University studies found the same brain activity pattern as seen in drug addicts and alcoholics. 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, yet could achieve erections with porn.
  3. Enhanced Attentional Bias towards Sexually Explicit Cues in Individuals with and without Compulsive Sexual Behaviours (2014) – 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].
  4. Novelty, Conditioning and Attentional Bias to Sexual Rewards (2015) – 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, porn addiction drives novelty-seeking in an attempt to overcome habituation and desensitization.
  5. Neural Substrates of Sexual Desire in Individuals with Problematic Hypersexual Behavior (2015) – 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 perfectly matched the prefrontal cortex activation patterns observed in drug addicts: Greater cue-reactivity to sexual images, yet inhibited response to other normal stimuli.
  6. 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/sex addiction. Not so. Steele et al. 2013 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. 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). Together these two Steele et al. findings indicate greater brain activity to cues (porn images), yet less reactivity to natural rewards (sex with a person). That”s sensitization & desensitization, which are hallmarks of an addiction. Eight peer-reviewed papers explain the truth: Peer-reviewed critiques of Steele et al., 2013. Also see this extensive YBOP critique.
  7. Modulation of Late Positive Potentials by Sexual Images in Problem Users and Controls Inconsistent with “Porn Addiction” (2015) – Another SPAN Lab EEG (brain-wave) study comparing the 2013 subjects from the above study 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, Nicole Prause, claims these results “debunk porn addiction”. What legitimate scientist would claim that their lone anomalous study has debunked an entire 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’s findings also align with Banca et al. 2015 which is #4 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. Ten peer-reviewed papers agree that this study actually found desensitization/habituation in frequent porn users (consistent with addiction): Peer-reviewed critiques of Prause et al., 2015
  8. HPA axis dysregulation in men with hypersexual disorder (2015) – 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 drug addiction.
  9. The Role of Neuroinflammation in the Pathophysiology of Hypersexual Disorder (2016) – 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.
  10. Methylation of HPA Axis Related Genes in Men With Hypersexual Disorder (2017) – 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.
  11. Compulsive sexual behavior: Prefrontal and limbic volume and interactions (2016) – 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 gray 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 is very stressful – and chronic social stress is related to increased amygdala volume. Study #8 above found that “sex addicts” have a overactive stress system. Could the chronic stress related to porn/sex addiction, along with factors that make sex unique, lead to greater amygdala volume?
  12. Can Pornography be Addictive? An fMRI Study of Men Seeking Treatment for Problematic Pornography Use (2017) – 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.
  13. Altered Appetitive Conditioning and Neural Connectivity in Subjects With Compulsive Sexual Behavior (2016) – A German fMRI study replicating 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”.
  14. Compulsivity across the pathological misuse of drug and non-drug rewards (2016) – A Cambridge University study comparing aspects of compulsivity in alcoholics, binge-eaters, video game addicts and porn addicts (CSB). Excerpts: CSB subjects were faster to learning from rewards in the acquisition phase compared to healthy volunteers and were more likely to perseverate or stay after either a loss or a win in the Reward condition. 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).
  15. Can pornography be addictive? An fMRI study of men seeking treatment for problematic pornography use (2017) – Excerpts: Men with and without problematic porn sue (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.
  16. Conscious and Non-Conscious Measures of Emotion: Do They Vary with Frequency of Pornography Use? (2017) – Study assessed porn user’s 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. An excerpt: 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.
  17. Preliminary investigation of the impulsive and neuroanatomical characteristics of compulsive sexual behavior (2009) – 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.
  18. Pornography Addiction Detection based on Neurophysiological Computational Approach (2018) An EEG study reporting several neurological differences between porn addicts and non-addicts. Unique in that the subjects average age was 14.
  19. Gray matter deficits and altered resting-state connectivity in the superior temporal gyrus among individuals with problematic hypersexual behavior (2018) – fMRI study. Summary: …study showed gray matter deficits and altered functional connectivity in the temporal gyrus among individuals with PHB (sex addicts). More importantly, the diminished structure and functional connectivity were negatively correlated with the severity of PHB. These findings provide new insights into the underlying neural mechanisms of PHB.
  20. Altered Prefrontal and Inferior Parietal Activity During a Stroop Task in Individuals With Problematic Hypersexual Behavior (Seok & Sohn, 2018) – [poorer executive control- impaired PFC functionality. Excerpt: Our findings suggest that individuals with PHB have diminished executive control and impaired functionality in the right DLPFC and inferior parietal cortex, providing a neural basis for PHB.
  21. Hypermethylation-associated downregulation of microRNA-4456 in hypersexual disorder with putative influence on oxytocin signalling: A DNA methylation analysis of miRNA genes (2019) – Study on subjects with hypersexuality (porn/sex addiction) reports epigenetic changes mirroring those occurring in alcoholics. The epigenetic changes occurred in genes associated with the oxytocin system (which is important in love, bonding, addiction, stress, sexual functioning, etc.).
  22. Gray matter volume differences in impulse control and addictive disorders (Draps et al., 2020) – Excerpts: Affected individuals compulsive sexual behavior disorder (CSBD), gambling disorder (GD), and alcohol use disorder (AUD) compared to controls showed smaller GMVs in the left frontal pole, specifically in the orbitofrontal cortex… Higher severity of CSBD symptoms was correlated with decreased GMV in the right anterior cingulate gyrus… Our findings suggest similarities between specific impulse control disorders and addictions.
  23. Normal Testosterone but Higher Luteinizing Hormone Plasma Levels in Men With Hypersexual Disorder (2020) – Excerpts: The proposed mechanisms might include the HPA and HPG interaction, the reward neural network, or the inhibition of regulation impulse control of prefrontal cortex regions.32 In conclusion, we report for the first time increased LH plasma levels in hypersexual men compared with healthy volunteers. These preliminary findings contribute to growing literature on the involvement of neuroendocrine systems and dysregulation in HD.
  24. High Plasma Oxytocin Levels in Men With Hypersexual Disorder (2020) – Excerpts: The results suggest hyperactive oxytonergic system in male patients with hypersexual disorder which may be a compensatory mechanism to attenuate hyperactive stress system. A successful CBT group therapy may have effect on hyperactive oxytonergic system.
  25. Inhibitory control and problematic Internet-pornography use – The important balancing role of the insula (2020) – Excerpts: Effects of tolerance and motivational aspects may explain the better inhibitory control performance in individuals with higher symptom severity which was associated with differential activity of the interoceptive and reflective system. Diminished control over IP use presumably results from the interaction between the impulsive, reflective, and interoceptive systems.
  26. Sexual cues alter working memory performance and brain processing in men with compulsive sexual behavior (2020) Excerpts: These findings are in line with the incentive salience theory of addiction, especially the higher functional connectivity to the salience network with the insula as a key hub and the higher lingual activity during processing of pornographic pictures depending on recent pornography consumption.
  27. Subjective reward value of visual sexual stimuli is coded in human striatum and orbitofrontal cortex (2020) –  Excerpts: We not only found an association of NAcc and caudate activity with sexual arousal ratings during VSS viewing but the strength of this association was greater when the subject reported more problematic pornography use (PPU). The result supports the hypothesis, that incentive value responses in NAcc and caudate differentiate more strongly between differently preferred stimuli, the more a subject experiences PPU. 
  28. The Neurosciences of Health Communication: An fNIRS Analysis of Prefrontal Cortex and Porn Consumption in Young Women for the Development of Prevention Health Programs (2020) – Excerpts: The results indicate that the viewing of the pornographic clip (vs. control clip) causes an activation of Brodmann’s area 45 of the right hemisphere. An effect also appears between the level of self-reported consumption and the activation of right BA 45: the higher the level of self-reported consumption, the greater the activation. On the other hand, those participants who have never consumed pornographic material do not show activity of the right BA 45 compared to the control clip (indicating a qualitative difference between non-consumers and consumers. These results are consistent with other research made in the field of addictions.
  29. Event-related potentials in a two-choice oddball task of impaired behavioral inhibitory control among males with tendencies towards cybersex addiction (2020) – Excerpts: Theoretically, our results indicate that cybersex addiction resembles substance use disorder and impulse control disorder in terms of impulsivity at electrophysiological and behavioral levels. Our findings may fuel the persistent controversy about the possibility of cybersex addiction as a novel type of psychiatric disorder.
  30. White matter microstructural and Compulsive Sexual Behaviors Disorder – Diffusion Tensor Imaging study (2020) – Excerpts: This is one of the first DTI studies assessing differences between patients with the Compulsive Sexual Behaviors Disorder and healthy controls. Our analysis has uncovered FA reductions in six regions of the brain in CSBD subjects, compared to controls. Our DTI data shows that the neural correlates of CSBD overlap with regions previously reported in the literature as related both, to addiction and OCD.

The above studies are all the “brain studies” published (or in the press) on internet porn users.

Together these brain studies found:

  1. The 3 major addiction-related brain changes: sensitization, desensitization, and hypofrontality.
  2. More porn use correlated with less grey matter in the reward circuit (dorsal striatum).
  3. More porn use correlated with less reward circuit activation when briefly viewing sexual images.
  4. More porn use correlated with disrupted neural connections between the reward circuit and prefrontal cortex.
  5. Addicts had greater prefrontal activity to sexual cues, but less brain activity to normal stimuli (matches drug addiction).
  6. 60% of compulsive porn addicted subjects in one study experienced ED or low libido with partners, but not with porn: all stated that internet porn use caused their ED/low libido.
  7. Enhanced attentional bias comparable to drug users. Indicates sensitization (a product of DeltaFosb).
  8. Greater wanting & craving for porn, but not greater liking. This aligns with the accepted model of addiction – incentive sensitization.
  9. Porn addicts have greater preference for sexual novelty yet their brains habituated faster to sexual images. Not pre-existing.
  10. The younger the porn users the greater the cue-induced reactivity in the reward center.
  11. Higher EEG (P300) readings when porn users were exposed to porn cues (which occurs in other addictions).
  12. Less desire for sex with a person correlating with greater cue-reactivity to porn images.
  13. More porn use correlated with lower LPP amplitude when briefly viewing sexual photos: indicates habituation or desensitization.
  14. Dysfunctional HPA axis which reflects altered brain stress circuits, which occurs in drug addictions (and greater amygdala volume, which is associated with chronic social stress).
  15. Epigenetic changes on genes central to the human stress response and closely associated with addiction.
  16. Higher levels of Tumor Necrosis Factor (TNF) – which also occurs in drug abuse and addiction.
  17. A deficit in temporal cortex gray matter; poorer connectivity between temporal corporate and several other regions

Neuro-Psychological Studies on Porn Users (with excerpts):

  1. Self-reported differences on measures of executive function and hypersexual behavior in a patient and community sample of men (2010)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.
  2. Watching Pornographic Pictures on the Internet: Role of Sexual Arousal Ratings and Psychological-Psychiatric Symptoms for Using Internet Sex Sites Excessively (2011)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
  3. Pornographic picture processing interferes with working memory performance (2013)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.
  4. Sexual Picture Processing Interferes with Decision-Making Under Ambiguity (2013) 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.
  5. Cybersex addiction: Experienced sexual arousal when watching pornography and not real-life sexual contacts makes the difference (2013)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.
  6. Cybersex addiction in heterosexual female users of internet pornography can be explained by gratification hypothesis (2014)Results indicated that Internet porn users rated pornographic pictures as more arousing and reported greater craving due to pornographic picture presentation compared with non-users. 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 porn users. Being in a relationship, number of sexual contacts, satisfaction with sexual contacts, and use of interactive cybersex were not associated with cybersex addiction.
  7. Empirical Evidence and Theoretical Considerations on Factors Contributing to Cybersex Addiction From a Cognitive Behavioral View (2014) 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.
  8. Prefrontal control and internet addiction: a theoretical model and review of neuropsychological and neuroimaging findings (2015)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.
  9. Implicit associations in cybersex addiction: Adaption of an Implicit Association Test with pornographic pictures. (2015)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. 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.
  10. Symptoms of cybersex addiction can be linked to both approaching and avoiding pornographic stimuli: results from an analog sample of regular cybersex users (2015)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.
  11. Getting stuck with pornography? Overuse or neglect of cybersex cues in a multitasking situation is related to symptoms of cybersex addiction (2015)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. The results of the current study point towards a role of executive control functions, i.e. functions mediated by the prefrontal cortex, for the development and maintenance of problematic cybersex use (as suggested by Brand et al., 2014). Particularly a reduced ability to monitor consumption and to switch between pornographic material and other contents in a goal adequate manner may be one mechanism in the development and maintenance of cybersex addiction.
  12. Trading Later Rewards for Current Pleasure: Pornography Consumption and Delay Discounting (2015)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. 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.
  13. Sexual Excitability and Dysfunctional Coping Determine Cybersex Addiction in Homosexual Males (2015) 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.
  14. Subjective Craving for Pornography and Associative Learning Predict Tendencies Towards Cybersex Addiction in a Sample of Regular Cybersex Users (2016)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
  15. Exploring the Relationship between Sexual Compulsivity and Attentional Bias to Sex-Related Words in a Cohort of Sexually Active Individuals (2016) – This study replicates the findings of this 2014 Cambridge University study that compared the attentional bias of porn addicts to healthy controls. The new study differs: rather than comparing porn addicts to controls, the new study correlated scores on a sex addiction questionnaire to the results of a task assessing attentional bias (explanation of attentional bias). The study described two key results: 1) Higher sexual compulsivity scores correlated with greater interference (increased distraction) during the attentional bias task. This aligns with substance abuse studies. 2) Among those scoring high on sexual addiction, fewer years of sexual experience were related to greater attentional bias. 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 section: “One possible explanation for these results is that as a sexually compulsive individual engages in more compulsive behaviour, an associated arousal template develops 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.”
  16. Mood changes after watching pornography on the Internet are linked to symptoms of Internet-pornography-viewing disorder (2016) – 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).
  17. Problematic sexual behavior in young adults: Associations across clinical, behavioral, and neurocognitive variables (2016) – Individuals with Problematic Sexual Behaviors (PSB) exhibited several neuro-cognitive deficits. These findings indicate poorer executive functioning (hypofrontality) which is a key brain feature occuring in drug addicts. A few excerpts: 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.
  18. Executive Functioning of Sexually Compulsive and Non-Sexually Compulsive Men Before and After Watching an Erotic Video (2017) – 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.
  19. Exposure to Sexual Stimuli Induces Greater Discounting Leading to Increased Involvement in Cyber Delinquency Among Men (2017) – 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-deliquency, 3) greater inclination to purchase counterfeit goods & 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: These findings provide insight into a strategy for reducing men’s involvement in cyber delinquency; that is, through less exposure to sexual stimuli and promotion of delayed gratification. 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.
  20. Predictors for (Problematic) Use of Internet Sexually Explicit Material: Role of Trait Sexual Motivation and Implicit Approach Tendencies Towards Sexually Explicit Material (2017) – Excerpts: The present study investigated whether trait sexual motivation and implicit approach tendencies towards 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.
  21. Tendencies toward Internet-pornography-use disorder: Differences in men and women regarding attentional biases to pornographic stimuli (2018) – Excerpts: Several authors consider Internet-pornography-use disorder (IPD) as addictive disorder. One of the mechanisms that has been intensively studied in substance- and non-substance-use disorders is an enhanced attentional bias toward addiction-related cues.  To investigate the role of attentional biases in the development of IPD, we investigated a sample of 174 male and female participants. Attentional bias was measured with the Visual Probe Task, in which participants had to react on arrows appearing after pornographic or neutral pictures. In addition, participants had to indicate their sexual arousal induced by pornographic pictures. Furthermore, tendencies toward IPD were measured using the short-Internet sex Addiction Test. The results of this study showed a relationship between attentional bias and symptom severity of IPD partially mediated by indicators for cue-reactivity and craving. The results support theoretical assumptions of the I-PACE model regarding the incentive salience of addiction-related cues and are consistent with studies addressing cue-reactivity and craving in substance-use disorders.
  22. Trait and state impulsivity in males with tendency towards Internet-pornography-use disorder (Antons & Brand, 2018) – Excerpts: In accordance with dual-process models of addiction, the results may be indicative of an imbalance between the impulsive and reflective systems which might be triggered by pornographic material. This may result in loss of control over the Internet-pornography use albeit experiencing negative consequences.
  23. Facets of impulsivity and related aspects differentiate among recreational and unregulated use of Internet pornography (Stephanie et al., 2019) Excerpts:  Individuals with unregulated use showed the highest scores for craving, attentional impulsivity, delay discounting, and dysfunctional coping, and lowest scores for functional coping and need for cognition. The results indicate that some facets of impulsivity and related factors such as craving and a more negative attitude are specific for unregulated IP users. The results are also consistent with models on specific Internet use disorders and addictive behaviors…. A further interesting result is that the effect size for post-hoc tests duration in minutes per session, when comparing unregulated users with recreational–frequent users, was higher in comparison to the frequency per week. This might indicate that individuals with unregulated IP use especially have difficulties to stop watching IP during a session or need longer time to achieve the desired reward, which might be comparable with a form of tolerance in substance use disorders.
  24. Approach bias for erotic stimuli in heterosexual male college students who use pornography (2019) – Excerpts: Overall, the findings suggest that approach for addictive stimuli may be a more rapid or prepared response than avoidance, which may be explained by the interplay of other cognitive biases in addictive behaviors….. Moreover, total scores on the BPS were positively correlated with approach bias scores, indicating that the greater the severity of problematic pornography use, the stronger the degree of approach for erotic stimuli….. Taken together, the results suggest parallels between substance and behavioral addictions (Grant et al., 2010). Pornography use (particularly problematic use) was linked to faster approaches to erotic stimuli than neutral stimuli, an approach bias similar to that observed in alcohol-use disorders (Field et al., 2008; Wiers et al., 2011), cannabis use (Cousijn et al., 2011; Field et al., 2006), and tobacco-use disorders (Bradley et al., 2004). An overlap between cognitive features and neurobiological mechanisms involved in both substance addictions and problematic pornography use seems likely, which is consistent with prior studies (Kowalewska et al., 2018; Stark et al., 2018).