Start here for an overview of key concepts

This website says nothing about the percentage of porn users who are addicted to Internet porn. This article is a  short synopsis of some key concepts. Watch the 6-part series Your Brain on Porn for a more in depth understanding. For porn-induced ED watch Erectile Dysfunction & Porn. For specific content explore Porn FAQ's.

What happens when you drop a male rat into a cage with a receptive female rat? First, you see a frenzy of copulation. Then, progressively, the male tires of that particular female. Even if she wants more, he has had enough. However, replace the original female with a fresh one, and the male immediately revives and gallantly struggles to fertilize her.

You can repeat this process with fresh females until he nearly dies of exhaustion.

This is called the Coolidge effect—the automatic response to novel mates. It’s what started you down the road to getting hooked on Internet porn.

Like that lab rat, you have a primitive mechanism in your brain urging you to fertilize the two-dimensional females, males (or whatever) on your screen. (Note: The Coolidge effect also occurs in females. Studies show that, when given the opportunity, human females are just as promiscuous as males.)

Primitive circuits in your brain govern emotions, drives, impulses, and subconscious decision-making. They do their jobs so efficiently that evolution hasn't seen the need to change them much since before humans were humans.

More dopamine, please

For you, rats, and all mammals, the desire and motivation to have sex arises from a neurochemical called dopamine. Dopamine amps up the centerpiece of the primitive part of the brain—the reward circuitry. It’s where we experience cravings and pleasure, and where we get addicted.

The ancient reward circuitry compels you to do things that further your survival and pass on your genes. At the top of our human reward list are food, sex, love, friendship, and novelty. These are called ‘natural reinforcers,’ as contrasted with addictive chemicals.

The evolutionary purpose of dopamine is to motivate you to do what serves your genes. The bigger the squirt the more you want something. No dopamine and you just ignore it. Chocolate cake and ice cream—a big blast. Celery—not so much. Sexual stimulation and orgasm are the biggest natural blast of dopamine available to your reward circuitry. One of dopamine's nicknames is the "molecule of addiction."

Although dopamine may be referred to as the "pleasure molecule," this may not be technically accurate. Dopamine is more the craving for pleasure, or measure of potential value. Although controversial, it appears that the final reward or good feelings arises from opioids. Dopamine is wanting, opioids are liking. Addiction may be thought of as wanting run amok.

Novelty, novelty, more novelty

Dopamine surges for novelty. A new car, just-released movie, the latest gadget…we are all hooked on dopamine. As with everything new the thrill fades away as dopamine plummets.

Here’s how the Coolidge effect works: The rat’s reward circuitry is squirting less and less dopamine with respect to the current female, but produces a big dopamine surge for a new female. Does that sound familiar?

Not surprisingly, rats and humans aren't that different when it comes to response to novel sexual stimuli. For example, when Australian researchers (graph) displayed the same erotic film repeatedly, test subjects' penises and subjective reports both revealed a progressive decrease in sexual arousal. The "same old same old" just gets boring. Habituation indicates declining dopamine.

After 18 viewings—just as the test subjects were nodding off—researchers introduced novel erotica for the 19^th and 20^th viewings. Bingo! The subjects and their penises sprang to attention. (Yes, women showed similar effects.)

Internet porn is especially enticing to the reward circuitry because novelty is always just a click away. It could be a novel “mate,” unusual scene, strange sexual act, or—you fill in the blank. With multiple tabs open and clicking for hours, you can experience more novel sex partners every ten minutes than our hunter-gatherer ancestors experienced in a lifetime.

What’s a brain to do when it has unlimited access to a superstimulating reward it never evolved to handle? Some brains eventually adapt, which can lead to addiction.

I can't emphasize this enough - Internet porn addiction is not a "sex addiction" - it's an Internet addiction. Although masturbation is often involved, this is an addiction to novel pixels on a screen.

Drugs aren’t the only addictions

It’s common knowledge that dopamine-raising substances, such as alcohol or cocaine, can create addictions. Yet only about 10-15% of humans or rats that use addictive drugs (except nicotine) ever become addicts. Does this mean the rest of us are safe from addiction? When it comes to substance abuse, perhaps yes.

Yet when it comes to unrestricted access to superstimulating versions of natural rewards, such as junk food, or even video games, the answer is no, although certainly not every user gets hooked.

The reason highly stimulating versions of food and sex can hook us—even if we're not otherwise susceptible to addiction—is that our reward circuitry evolved to drive us toward food and sex, not drugs. Today’s high fat/sugar foods (75% of American adults are overweight, 35% obese) and Internet porn (you’re reading this) have the potential to hook even more people than do drugs. These supernormal versions of natural rewards can override our brain’s satiation mechanisms—the “I’m done” feeling—because concentrated calories and fertilization opportunities are your genes’ top priorities.

All addictions lead to the same major brain changes

Recent research reveals that behavioral addictions (food addiction, pathological gambling, video gaming, and Internet addiction) and substance addictions involve the same fundamental mechanisms leading to a collection of shared alterations in brain anatomy and chemistry. These brain changes include:

1. Desensitization ("A numbed pleasure response"): Among other changes, dopamine and dopamine (D2) receptors decline in the brain's reward circuitry, leaving the addict less sensitive to pleasure, and "hungry" for dopamine-raising activities/substances of all kinds. The addict then tends to neglect interests, stimuli, and behaviors that were once of high personal relevance.
2. Sensitization ("A super memory of pleasure"): Rewired nerve connections cause the reward circuitry to buzz in response to addiction-related cues or thoughts. This Pavlovian memory makes the addiction more compelling than other activities in the addict's life.
3. Hypofrontality ("Willpower erodes"): Alterations in frontal-lobe gray matter and white matter correlate to reduced impulse control and the weakened ability to foresee consequences.

Are these the only brain changes? No. Each of these broad-brush indicators reflect multiple subtler addiction-related cellular and chemical alterations—just as the scan of a cancer tumor wouldn't show associated subtler cellular/chemical changes.

Most of the subtler changes can't be assessed in human models due to the invasiveness of the technologies required. However, they have been identified in animal models.

Same master switch for sex/food as for drug addiction: DeltaFosB

The master switch that triggers many of these addiction-related changes is the protein DeltaFosB. Continued over-consumption of natural rewards (sex, sugar, high-fat, aerobic exercise) or chronic administration of virtually any drug of abuse causes DeltaFosB to accumulate in the reward circuitry. It's important to understand that addictive drugs only cause addiction because they magnify or inhibit mechanisms already in place for natural rewards.

DeltaFosB's evolutionary purpose is to motivate us to "get it while the getting is good!" It's a binge mechanism for food and reproduction, which worked well in other times and environments. With the advent of super-normal versions of natural rewards, it makes addictions to junk food and Internet porn as easy as 1-2-3. This is why the American Society of Addiction Medicine unambiguously states that food and sex addictions are true addictions (see below).

Your hijacked binge mechanism: Dopamine activates DeltaFosB 

A "binge mechanism" is an evolutionary advantage in situations where survival is furthered by overriding normal satiety. Think of wolves, which need to stow away up to twenty pounds of a single kill at one go. Or our ancestors, who needed to store high-quality calories as a few extra pounds for easy transport to survive hard times. Or mating season, when there's a harem to impregnate. In the past, such opportunities were rare and passed quickly.

Our environments have drastically changed. The Internet offers endless mating opportunities, which your primitive brain perceives as real because you find them so exciting. As any good mammal would, you automatically attempt to spread your genes far and wide, but there’s no end to your mating season.

Click, click, click, masturbate, click, click, click, masturbate, click, click, click. Day in and day out, never taking a break. This can kick your binge mechanism into overdrive. Evolution never prepared your primitive brain for this kind of nonstop stimulation.

Excess consumption (food or sex) is the signal to your primitive brain that you have hit the evolutionary jackpot. With continued daily over-consumption dopamine triggers the accumulation of DeltaFosb, which initiates several brain changes, including sensitization.

Overconsumption → dopamine → DeltaFosB → addiction-related changes

The obvious question is: "How much is too much?" The answer is simple: "Whatever amount of stimulation causes the accumulation of DeltafosB and the corresponding brain changes."

This is why posing such questions as "What is the definition porn?" or "How much porn use constitutes an addiction?" are misleading and irrelevant. The former is like asking whether it's slot machines or blackjack that leads to a gambling addiction.  The latter is like asking a food addict how many minutes she spends eating.

The reward circuitry doesn't know what porn is. It only registers levels of stimulation through dopamine spikes. This is physiology, not morality or sexual politics.

Sensitization: A Pavlovian super-memory is formed

Learning, memory, and habits can be summed up in the old, but true, saying - "Nerve cells that fire together, wire together"

The rewiring behind addiction arises partly from overproduction of natural chemicals (delta FosB), and the strengthening the connections between nerve cells, making it easier for them to communicate. This is what happens in all learning. It’s called neuroplasticity. The more intense the experience, the stronger the connections. The stronger the connections, the easier it is for electrical impulses to travel along this new pathway.

If habitual porn viewing has caused addiction-related brain changes, you have forged a rut in your brain. Just as water flows through the path of least resistance, so do impulses, and thus thoughts. As with any skill, the more you practice the easier it is do. Soon it becomes automatic, without any conscious thought. You've formed a deep pornography rut in your brain: a sensitized neural pathway.

Sensitized pathways can be thought of as Pavlovian conditioning on steroids. When activated by thoughts or triggers, sensitized pathways blast the reward circuit, firing up hard-to-ignore cravings.

More pleasure leads to less pleasure (desensitization)

As sensitization and cravings compel you to use porn, overstimulation of the reward circuitry leads to a localized rebellion. The nerve cells bombarded by dopamine say "enough is enough."  If someone continues to scream, you cover your ears. When dopamine-sending nerve cells keep pumping out dopamine, the receiving nerve cells cover their "ears" by reducing dopamine (D2) receptors.

The cycle of desensitization mimics other addictions:

bingeing→ cravings→ numbed pleasure response→ cravings→ bingeing escalates→ further decline in dopamine & dopamine receptors→ further desensitization...

And soon you are hooked on porn, because nothing else is anywhere near as interesting to your brain. From your genes’ perspective, it’s the perfect design—to keep you fertilizing frantically—before this "valuable mating opportunity" slips away.

As desensitization numbs you to everyday pleasures, sensitization makes your brain hyper-reactive to anything associated with your porn addiction. Over time, this dual-edged mechanism can have your reward circuitry buzzing at the hint of porn use, but less than enthused when presented with the real deal. Desensitization is not "damage". If your cells wanted, they could rebuild loss dopamine receptors in a few minutes. Rather, desensitization represents a negative feed back system in overdrive.

If these two neuroplastic changes could speak, desensitization would be moaning, "I can't get no satisfaction" (low dopamine signaling), while sensitization would be poking you in the ribs and saying, "Hey buddy, I got just what you need," which happens to be the very thing that caused the desensitization.

A numbed pleasure response (desensitization), combined with a deep pathway leading to short-term relief (sensitization), is the basis of all addictions.

Escalation and rewiring

Developing tolerance (numbed pleasure response) means an addict needs more of his/her "drug" to get the same effect. Heavy porn users sometimes notice that as tolerance builds for their earlier tastes, they move in new directions in their search for intense arousal. Many seek out what shocks them—perhaps because "forbidden" and "fear-producing," plus sexual arousal, offer a bigger brain-chemical kick...at least for a time.

So, it's not unusual to start out your porn career with an image of a famous hottie's fine butt—and months later find you have "progressed" to girls with goats or violent rape scenes. Keep in mind that that when an addict escalates to new genres or longer use he is driven by desensitization. His fundamental sexual orientation has not changed.

The more intense the associated events (orgasm + video), or the more they are repeated, the stronger the wiring. Each experience wires the new tastes into the brain. If your sexual tastes have changed, so has your brain.

Definition of addiction?

Many still believe that only chemicals, not behaviors such as Internet porn, can cause addiction. However, neuroscientists who study the effects of addiction on the brain know differently. Experts in the field define addiction in many ways. A simple model for understanding addiction is to apply the four Cs:

1. Compulsion to use
2. Continued use in spite of adverse consequences
3. Inability to Control use
4. Craving - psychological or physical

Addiction may be accompanied by physical dependence and withdrawal symptoms. Many heavy porn users are surprised by the severity of their withdrawal symptoms, which overlap with those experienced by cocaine addicts and alcoholics. (Take this quiz to see if the addiction process is taking hold in your brain.)

Note that The American Society for Addiction Medicine emphasized this simple concept based on decades of research: Exhibiting the signs, symptoms and behaviors associated with addiction indicates the underlying brain changes have occurred.

Science moves on

For political reasons, brain research isolating Internet porn addicts from plain old Internet addicts is not being done. However, several brain studies on "Internet addicts" were published after this article was initially written, and all found the same brain changes as seen in drug addicts. The studies did not assess what percentage of research subjects were addicted to Internet porn. However, it’s illogical to conclude that high levels of Internet porn use cannot change the brain, when junk food, video games, gambling, and "the Internet" have already been proven to do so (see Recent Internet Addiction Studies Include Porn).

The American Society of Addiction Medicine (ASAM) hammered the final nail in the porn debate coffin in August, 2011, ten months after I first wrote this intro. America’s top addiction experts at ASAM released their sweeping new definition of addiction. The new definition echoes the major points made on this website. Foremost, behavioral addictions affect the brain in the same fundamental ways as drugs do. In other words, addiction is one disease (condition), not many. For all practical purposes, this new definition ends the debate over whether sex and porn addictions are “real addictions.” ASAM explicitly states that sexual behavior addictions exist and must be caused by the same major brain changes found in substance addictions.

Those who scream "pseudoscience" at the mention of Internet porn addiction either have a political agenda or are unaware of recent advances in neuroscience.

To summarize the current state of addiction neuroscience:

• Extensive research on behavioral addictions reveals the same fundamental brain changes that occur with chemical addictions.
• Those with addiction-related behaviors and symptoms have a specific set of measurable brain alterations.
• The brain changes found in all addictions include sensitization, desensitization, hypofrontality, and abnormal white matter.
• Addiction-related brain changes (both behavioral and chemical) are triggered by accumulation of DeltaFosB. There's one molecular switch, whether drug, gambling, food, or Internet porn addiction is at work.
• The brain research done thus far on Internet addiction (which includes porn use) reveals all the aforementioned brain changes.
• Evidence from two recent Internet addiction studies shows that in control groups of former Internet addicts, the harmful brain changes had already begun to reverse themselves

"Pseudoscience" is:

• ignoring all anecdotal, clinical, and research evidence that points to Internet porn addiction as a true addiction.
• ignoring multiple brain studies on Internet addiction disorder.
• believing that the signs, symptoms and behaviors of Internet porn addiction must arise from some unidentified mechanisms other than addiction.
• replacing the word addiction with compulsion, yet providing no research or hypothesis on what makes a compulsion different from an addiction.
• ignoring researchers at ASAM who provide the hard data of addiction neuroscience.
• suggesting that porn has been around forever, and that staring at cave drawings is no different than watching 30 tabs of hard-core while clicking from scene to scene.
• suggesting that Internet porn addiction must be the one and only exception to the rule - an addiction that is somehow not an addiction.

 What makes Internet porn unique?

It’s evident that today's porn is easy to access, available 24/7, free and private. The way it's used keeps dopamine elevated for abnormally long periods, making Internet porn uniquely compelling, and potentially addictive (note - we don't speak to the psychological impact of young people watching hard-core porn of every type imaginable and umimaginable).

Recovery sites often stress that the addictiveness of Internet porn is due to masturbation and orgasm becoming linked to exciting or shocking visuals. Certainly both play a role, but what sets Internet porn apart is:

1. It affords extreme novelty—hundreds of new sexual partners per session. Novelty is highly stimulating. Today's porn is not Dad’s static, finite Playboy. Users often report that "real sex" grows boring by comparison.
2. Unlike food and drugs, in which there is a limit to consumption, there are no physical limitations to Internet porn consumption. The brain’s natural satiation mechanisms are not activated, unless one climaxes. Even then, the user can click to something more exciting to become aroused again.
3. With food and drugs one can only escalate (a marker of an addiction process) by consuming more. With Internet porn one can escalate both with novel "partners" and by viewing new and unusual genres. It’s quite common for a user to move to ever more extreme porn.
4. Unlike drugs and food, Internet porn doesn't eventually activate the brain’s natural aversion system. Aversion is when you don’t like how a drug or too many mashed potatoes make you feel.
5. The age users start watching porn. A teen's brain is at its peak of dopamine production and neuroplasticity, making it highly vulnerable to addiction and rewiring. Adolescent animals produce higher levels of DeltaFosB in respones to drugs and natural rewards.

Many symptoms, one cause

People arrive here with lots of different symptoms, which they're not always sure are due to their heavy porn use. Confusion is understandable because the symptoms look so different:

• Distress about escalation to more extreme porn
• Delayed ejaculation
• Copulatory impotence (can get it up for porn, but not partners)
• Frequent masturbation, little satisfaction
• Uncharacteristic, worsening social anxiety or lack of confidence
• Growing erectile dysfunction, even with extreme porn.
• Morphing porn tastes that don't match sexual orientation (such as HOCD)
• inability to concentrate, extreme restlessness
• Depression, anxiety, brain fog

There's good reason to believe these symptoms arise from addiction-related brain changes, as the reward circuit contains structures that influence emotions, moods, cognitive function, stress response, the autonomic nervous system, and the endocrine system.

Rebalancing the brain

If this phenomenon is underlying your symptoms, you need to restore the sensitivity of your reward circuit, weaken sensitized addiction pathways, and strengthen executive control. We call this process "rebooting." The best way to reboot is to give your brain a rest from all intense artificial sexual stimulation— including porn, fantasizing about porn, chat rooms, erotic stories, surfing for pictures—until it bounces back to normal responsiveness. 

Those addicted to porn often find the rebooting process easier and faster when they drastically reduce or eliminate masturbation. This abstinence from masturbation and orgasm isn't a lifestyle; it's a temporary method for deepening recovery and reducing relapses into porn. Obviously, this process is initially very difficult. The brain can no longer rely on the artificially intense "fix" of dopamine (and other neurochemicals) associated with heavy porn use.

In addition to desensitization, porn use strengthens nerve connections linking the short-term relief of Internet porn with any trigger your brain associates with porn (sensitization). Triggers such as being home alone, sexy images, or stress and anxiety, can activate your brain's porn rut. The only way to weaken these subconscious links is to stop using (reinforcing) that brain pathway, and seek your mood medicine elsewhere. Eliminating porn and porn fantasy leads to "un-wiring" and eventual weakening of sensitized pathways and cravings.

The other half of the rewiring process involves strengthening your executive control, which resides in your frontal cortex (behind your forehead). Assessing risk, making long-range plans, and controlling impulses are under the control of the frontal cortex. The term hypofrontality is often used when describing how addictions weaken and inhibit these self-control circuits. It takes time, and consistency, to return these circuits to full working order.

Remember: Your freedom lies in rebalancing your brain. Then you can choose whether you will activate your porn-arousal pathway or some pathway that yields results you prefer. Needless to say, rebooting doesn't guarantee you can safely use Internet porn in the future. The human brain remains vulnerable to a downward spiral from too much of any intense stimulus, and your brain has a sensitized porn pathway, which can always be reactivated.

Many have stopped using porn and recovered their lives. So can you.

For a more in-depth understanding of the science behind Internet porn addiction, I suggest reading these articles in the following sequence:

• Intoxicating Behaviors: 300 Vaginas = A Lot of Dopamine: We are easily hooked by supernormal versions of natural rewards
• Porn, Novelty and the Coolidge Effect: Without the Coolidge Effect there would be no Internet porn
• Porn Then and Now: Welcome to Brain Training: "Are we the first generation to masturbate left-handed?"
• Why Shouldn't Johnny Watch Porn If He Likes?: Sexual brain training matters—especially during adolescence
• Why Do I Find Porn More Exciting Than A Partner?: Neuroscience reveals how Internet porn can trump real sex
• Can You Trust Your Johnson?: Is Internet porn making male sexuality more plastic?
• Recent Internet Addiction Studies Include Porn: Brain research on Internet addiction points in only one direction
• The Other Porn Experiment: What can informal control groups of former porn users show us?
• Toss Your Textbooks: Docs Redefine Sexual Behavior Addictions: American Society of Addiction Medicine releases their sweeping new definition of addiction.