Start here for a brief overview of concepts & science

Printer-friendly version
This article is a short synopsis of some key concepts. For the science behind it, please follow all the links and read this page. Some links go to our articles, which in turn link to studies. For a more in-depth understanding and further evidence see The Research Page. For specific content explore Porn FAQs.


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 is completely wiped out.

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, hunter-gatherer females are no less promiscuous than 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 pursue sex arises largely 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 offers the biggest natural blast of dopamine available to your reward circuitry. One of dopamine's nicknames is the "molecule of addiction" because it plays a central role in all addictions.

Although dopamine is often referred to as a "pleasure molecule," this is not technically accurate. Dopamine is all about seeking and searching for rewards, the anticipation, the wanting, Dopmine provides the motivation and drive to pursue potential rewards or long term goals. Although controversial, it appears that the final reward or good feelings arises from opioids. Put simply - Dopamine is wanting, opioids are liking.

As psychologist Susan Weinschenk explained in a 2009 article, the neurotransmitter dopamine does not cause people to experience pleasure, but rather causes a seeking behavior. “Dopamine causes us to want, desire, seek out, and search,” she wrote. It is the opioid system that causes one to feel pleasure. Yet, “the dopamine system is stronger than the opioid system,” she explained. “We seek more than we are satisfied.” 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 19th and 20th 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. Research confirms anticipation of reward and novelty amplify one another to increase excitement and rewire the limbic brain. Internet porn is what scientists call a supernormal stimulus.

Supernormal Stimulus

So what makes today's porn uniquely compelling? Not just its unending novelty. Dopamine fires up for other emotions and stimuli too, all of which often feature prominently when using internet porn:

Erotic words and pictures have been around a long time. So has the neurochemical rush from novel mates. Yet the novelty of a once-a-month Playboy evaporates as soon as you turn the pages. Would anyone call Playboy or softcore videos "shocking" or "anxiety-producing?" Would either violate the expectations of a computer-literate boy over the age of 12? Neither compares with the "searching and seeking" of a multiple-tab Google prowl. What makes Internet porn unique is that you can control your dopamine with the click of a mouse or tap on a screen.

Many of these same emotional states (anxiety, shame, shock, surprise) not only elevate dopamine, each can boost brain norepinephrine or circulating stress hormones (adrenaline, cortisol). These stress neurochemicals increase excitement while amplifying dopamine's already powerful effects. Over time a porn user’s brain can mistake feelings of anxiety or fear with feelings of sexual arousal. This helps explain why some porn users escalate into ever more shocking or anxiety invoking porn – they need that extra neurochemical jolt just to become sexually aroused, or to orgasm

What’s a brain to do when it has unlimited access to a super-stimulating reward it never evolved to handle? Some brains eventually adapt, which can lead to addiction-related brain changes or sexual conditioning.

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.

Drug addictions 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 super-stimulating 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.

Addictions share many of the same mechanisms & fundamental brain changes

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

This is not surprising as drugs can only enhance or inhibit normal physiological functions. The specific way a drug alters cellular function is called its "mechanism of action". All drugs and behaviors that can potentially cause addiction share one important mechanism of action: elevation of dopamine in the nucleus accumbens (also called the reward center).

Addiction-related brain changes include:

  1. Desensitization ("A numbed pleasure response"): Among other changes, dopamine and dopamine 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. Desensitization often manifests as the need for greater and greater stimulation to achieve the same buzz (‘tolerance’). You many spend more time online, prolonging sessions through edging, watching when not masturbating, or searching for the perfect video to end with. Desensitization can also take the form of escalating to new genres, sometimes harder and stranger, or even disturbing. Remember: shock, surprise and anxiety can jack up dopamine.
  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. Cues, such as turning on the computer, seeing a pop-up, or being alone, trigger intense cravings for porn.  Some describe a sensitized porn response as ‘entering a tunnel that has only one escape: porn’. Maybe you feel a rush, rapid heartbeat, even trembling, and all you can think about is logging onto your favorite tube site. These are examples of sensitized addiction pathways activating your reward circuit, screaming, ‘Do it now!’
  3. Hypofrontality ("Willpower erodes"): Alterations in frontal-lobe gray matter and white matter correlate with reduced impulse control and the weakened ability to foresee consequences. Hypofrontality shows up as the feeling that two parts of your brain are engaged in a tug-of-war. The sensitized addiction pathways are screaming ‘Yes!’ while your ‘higher brain’ is saying, ‘No, not again!’ While the executive-control portions of your brain are in a weakened condition the addiction pathways usually win.
  4. Dysfunctional stress circuits - which can make even minor stress lead to cravings and relapse because they activate powerful sensitised pathways.

Are these the only brain changes? No. Each of these broad-brush indicators reflects 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. For supporting science, see this review Natural Rewards, Neuroplasticity, and Non-Drug Addictions (2011)

A common molecular switch for sexual conditioning and addiction: DeltaFosB

The molecular switch that initiates many of these addiction-related behaviors 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 slowly 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.

The accumulation of DeltaFosB and the molecular changes it generates are nearly identical for both sexual conditioning and drugs of abuse. In other words, DeltaFosB evolved to rewire the brain to sexual stimuli, yet drugs hijack this very same mechanism. In fact, methamphetamine activates the exact same nerve cells in the reward center as do sexual rewards. In contrast, there's only a small percentage of nerve-cell activation overlap between meth and food or water (other natural rewards).

Surprisingly, ejaculation in male rats can shrink the reward circuit nerve cells that produce dopamine. This normal event mimics the effects of heroin addiction on these same dopamine nerve cells. This doesn't mean sex is bad. It simply informs us that addictive drugs hijack the exact same mechanisms that urge us back into the bedroom for a romp.

Put simply, addictive drugs like meth & heroin are compelling because they hijack the precise nerve cells and mechanisms, which evolved to make sex compelling. Most other pleasures do not. Thus, the familiar "talking point" that "Everything raises dopamine. Golf or laughing are certainly not addictive, and how different can they be from internet porn in terms of dopamine increases?" falls apart.

The important take-away concept is that drugs can activate the "sex" neurons and trigger a buzz without actual sex. So can internet porn. Golf and laughing cannot. For that matter, nor can good old rock & roll.

One of 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 commonality for all addictions is why the American Society of Addiction Medicine (3,000 addiction MDs and researchers) 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 (update-compulsive eating circuit found).

Our environments have drastically changed. The Internet offers endless mating opportunities, which your primitive brain perceives as real because you find them so arousing. 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 center (nucleus accumbens) 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 (DeltaFosB), and the strengthening of 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 turbos. When activated by thoughts or triggers, sensitized pathways blast the reward circuit, firing up hard-to-ignore cravings. Two recent brain studies of compulsive porn users assessed sensitization, and both reported the same brain response as seen in alcoholics and drug addicts (see - Cambridge University: Brain scans find porn addiction).

DeltaFosB slowly degrades, and is back to normal levels about 2 months after an addict last uses. Even though DeltaFosB is no longer present, the sensitized addiction pathways remain, perhaps for a lifetime. Remember, the purpose of DeltaFosB is to promote the rewiring of the brain, so that you will experience a bigger blast from whatever you have been overconsuming. Put simply, the memory lingers long after the event - and addiction is a super memory.

More pleasure seeking 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. In addition, desensitization may involve a decline in dopamine and opioids, and a loss of nerve connections (grey matter). To make matters worse, D2 receptors help put the brakes on over-consumption, so their loss means cravings are harder to resist.

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.

Desensitization numbs you to everyday pleasures, while 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." Your cells could rebuild lost dopamine receptors rapidly. Rather, desensitization represents a negative feedback system in overdrive. A 2014 brain study on porn users found that greater porn use was associated with greater desensitization (loss of reward circuit grey matter, less sexual arousal).

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 cravings and 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 least for a time.

Porn addiction escalation is like running on a hamster wheelSo, 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 logs more hours of use in search of satisfaction, 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

At this time, three studies have examined the brains of porn users:

  1. Brain Structure and Functional Connectivity Associated With Pornography Consumption: The Brain on Porn (2014). A German study which found 3 significant addiction-related brain changes that correlated with the amount of porn consumed. It also found that the more porn consumed the less activity in the reward circuit, indicating desensitization, and increasing the need for greater stimulation (tolerance).
  2. Cambridge University: Brain scans find porn addiction (2014). This is the first in a series of studies. It found the same brain activity 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. One other major finding (not reported in the media), was that over 50% of subjects (average age: 25) had difficulty achieving erections or 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 above studies provide very strong support for hypotheses put forth by YBOP a few years ago. The findings include:

  • The 3 major addiction-related brain changes discussed in YBOP videos & articles: sensitization, desensitization, and hypofrontality.
  • Less arousal to sexual imagery (the need for greater stimulation).
  • The younger the porn user the greater the cue-induced reactivity in the reward center.
  • Young, compulsive porn users stating that porn use caused their copulatory erectile dysfunction

For political reasons, brain research isolating Internet porn addicts from plain old Internet addicts has been very slow in arriving. In addition to the above brain studies, over 100 brain studies on "Internet addicts" have been published, and all have found the same fundamental brain changes as seen in drug addicts. The studies did not assess what percentage of research subjects were addicted to Internet porn. However, it would be 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 this intro article appeared. 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. In fact, a newly created behavioral addiction category appears in the new DSM-5, and, in time, Internet addictions will have to be added to bring the DSM into alignment with addiction research (see - National Institute of Mental Health: DSM is flawed and outdated.)

Here's a excellent peer-reviewed journal article of where addiction neuroscience is with respect to porn addiction: Pornography addiction – a supranormal stimulus considered in the context of neuroplasticity (2013).

Those who shout "pseudoscience" at the mention of Internet porn addiction either have a political agenda or are unaware of recent advances in addiction 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, altered stress responses, 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.
  • Evidence that Internet addiction appears to cause depression and multiple other symptoms has come out in recent studies.
  • The DSM-5 field studies conclude that hypersexual disorder exists. (However, "hypersexual" is a misleading term, which denies the behavioral addiction research findings.)

"Pseudoscience" is:

  • Ignoring all anecdotal, clinical, and research evidence that points to Internet porn addiction as a true addiction.
  • Ignoring the only brain scan studies on porn users (link1, link2).
  • Ignoring multiple brain studies on Internet addiction disorder.
  • Believing (without scientific basis) that the signs, symptoms and behaviors of Internet porn addiction must arise from unidentified mechanisms other than addiction.
  • Replacing the word addiction with compulsion, yet providing no research or hypothesis as to what makes a "compulsion to use X" different from "an addiction to X."
  • Ignoring the medical doctors and addiction neuroscientists of ASAM who clearly state that sexual behavior addictions exist.
  • Suggesting that porn has been around forever, and that staring at cave drawings is no different than watching 20 tabs of hardcore video while clicking from scene to scene.
  • Ignoring neuroscience on the adolescent brain, which shows it is far more vulnerable to sexual conditioning and addiction than the adult brain. (See - Children becoming addicted to porn.)
  • Suggesting that Internet porn addiction must be the one and only exception to the behavioral-addiction 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 escalating to hardcore porn of every type imaginable and unimaginable, while highly aroused during a masturbation session - something our ancestors couldn't do.)

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 to today's parade of erotica-at-a-click.
  2. Unlike food and drugs, for 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 more 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. Video is more arousing than static porn.
  6. 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 response to drugs and natural rewards.

Internet porn addiction is not sex addiction

Sex addiction requires real people; porn addiction requires a screen and an Internet connection. The majority of guys we see started on Internet porn long before any sexual contact: young guys who rewired their adolescent sexuality to clicking, searching, voyeurism, multiple tabs, HD streaming hardcore - long before their first kiss. Does this sound like a Tiger Woods-esque addiction? 

Any debates on porn addiction should therefore exclude all mention of sex addiction or how  "normal male behavior" is being pathologized. When did normal sexual behavior evolve into staring at a screen, masturbating with your non-dominant hand, while clicking through scene after scene, searching for "the one" to finish off? 

Can masturbation play a role in this addiction?

Of course, but masturbation is not required. That said, frequent ejaculation in animals leads to several brain changes that inhibit dopamine, and thus libido, for several days. Under normal circumstances, sexual satiety (defined differently for each species) leads to males taking a time out from sexual activity. Sexually satiated porn users may override these inhibitory mechanisms by escalating to extreme porn, or spending more time watching. Both goose dopamine. Pushing past "I'm done" signals can lead to the accumulation of DeltaFosB. Certainly, eating to obesity causes the accumulation of DeltaFosB. However, without the lure of Internet porn, how many guys would just give it a rest? Most all. For more, see Does Frequent Ejaculation Cause A Hangover?

Note: Many threads link to YBOP. Most debates about porn addiction (existence or effects) devolve into debates about masturbation. This is nonsensical and completely muddies the discussion. YBOP is only concerned with Internet porn use, not the pros, cons, or frequency of masturbation.

Many symptoms, one cause:

Bummed guy in bedPeople 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:

There's good reason to believe these symptoms can often 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. For example, many of the above complaints such as social anxiety, depression, low motivation, ED, and concentration problems, have been linked to low dopamine and low or altered D2 receptors. For the neurobiology of the many benefits ex-porn users experience, see Porn, Masturbation and Mojo: A Neuroscience Perspective.

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 spending time with real potential mates. Affectionate contact is healthful for both partners and can help you rewire your arousal to real people. When to have sex? After a time-out (the length of which varies depending upon individual circumstances), some guys find that resuming sexual activity with a real partner is especially helpful, as long as they (and their partners) don't try to force ejaculation until it happens naturally.

Eliminating porn use often strengthens 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, read these articles in sequence (follow the embedded links for citations):