Addiction Research and Articles About Research
Below this long intro are many sub-sections containing relevant studies.
- See Questionable & Misleading Studies for highly publicized papers that are not what they claim to be.
Understanding Internet porn addiction means understanding addiction mechanisms. All addictions hijack the same core neurocircuitry, which runs on the same neurochemicals (even though each addiction also involves additional neural circuits and neurochemicals that differ between addictions).
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 existing 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 (often called the reward center). In light of the latest scientific advances, the criticisms of the sexual-behavior addiction model are unfounded and outdated (and no studies have yet to falsify the porn addiction model). Recent reviews of the literature support this position:
- 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 and Gary Wilson, 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. A second 2016 paper by Gary Wilson discusses the importance of studying the effects of porn by having subjects abstain from porn use: Eliminate Chronic Internet Pornography Use to Reveal Its Effects (2016).
- See this 2015 paper by two medical doctors: Sex Addiction as a Disease: Evidence for Assessment, Diagnosis, and Response to Critics (2015), which provides a chart from that takes on specific criticisms and offers citations that counter them.
- For a thorough review of the neuroscience literature related to Internet addiction subtypes, with special focus on internet porn addiction, see - 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. (See this page for critiques and analysis of highly questionable and misleading studies)
- 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.
- A short review - Neurobiology of Compulsive Sexual Behavior: Emerging Science (2016) - which concluded: "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."
- A 2016 review of compulsive sexual behaviors (CSB) - Should compulsive sexual behavior be considered an addiction? (2016) - concluded that: "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." Note: most of the neuroscience supporting the existence of "sex addiction" actually comes from studies on porn users, not sex addicts. Conflating internet porn addiction with sex addiction weakens the paper.
- 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."
- While the term "hypersexuality" should be discarded, this is a pretty good review by Max Planck neuroscientists 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."
- 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.
- 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.
- 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.
Four major brain changes are involved with both drug and behavioral addictions, as outlined in this paper published this year in The New England Journal of Medicine: "Neurobiologic Advances from the Brain Disease Model of Addiction (2016)". This landmark review by the Director of the National Institute on Alcohol Abuse and Alcoholism (NIAAA) George F. Koob, and the director of the National Institute on Drug Abuse (NIDA) Nora D. Volkow, not only outlines the brain changes involved in addiction, it also states in its opening paragraph that sex addiction exists:
"We conclude that neuroscience continues to support the brain disease model of addiction. Neuroscience research in this area not only offers new opportunities for the prevention and treatment of substance addictions and related behavioral addictions (e.g., to food, sex, and gambling)...."
In simple, and very broad, terms the major fundamental addiction-caused brain changes are: 1) Sensitization, 2) Desensitization, 3) Dysfunctional prefrontal circuits (hypofrontality), 4) Dysfunctional stress circuits. All 4 of these brain changes have been identified among the 30 or so neuroscience-based studies on frequent porn users & sex addicts:
- Sensitization (cue-reactivity & cravings): Brain circuits involved in motivation and reward seeking become hyper-sensitive to memories or cues related to the addictive behavior. This results in increased "wanting" or craving while liking or pleasure diminishes. For example, cues, such as turning on the computer, seeing a pop-up, or being alone, trigger intense hard to ignore 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. Studies reporting sensitization or cue-reactivity in porn users: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18.
- Desensitization (decreased reward sensitivity): This involves long-term chemical and structural changes that leave the individual less sensitive to pleasure. Desensitization often manifests as tolerance, which is the need for a higher dose or greater stimulation to achieve the same response. Some porn users 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 or anxiety can jack up dopamine. Some studies use the term "habituation," which may involve learning mechanisms or addiction mechanisms. Studies reporting desensitization or habituation in porn users/ sex addicts: 1, 2, 3, 4, 5, 6.
- Dysfunctional prefrontal circuits (weakened willpower + hyper-reactivity to cues): Alterations in prefrontal functioning and connections between the reward circuit and the frontal lobe lead to reduced impulse control, yet greater cravings to use. Dysfunctional prefrontal circuits show 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. Studies reporting "hypofrontality" or altered prefrontal activity in porn users: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.
- Dysfunctional stress circuits - which can result in even minor stress leading to cravings and relapse because it activates powerful sensitized pathways. Studies reporting dysfunctional stress responses in porn users/ sex addicts: 1, 2, 3.
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.
Together the above brain studies found:
- The 3 major addiction-related brain changes: sensitization, desensitization, and hypofrontality.
- More porn use correlated with less grey matter in the reward circuit (dorsal striatum).
- More porn use correlated with less reward circuit activation when briefly viewing sexual images.
- More porn use correlated with disrupted neural connections between the reward circuit and prefrontal cortex.
- Addicts had greater prefrontal activity to sexual cues, but less brain activity to normal stimuli (matches drug addiction).
- 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.
- Enhanced attentional bias comparable to drug users. Indicates sensitization (a product of DeltaFosb).
- Greater wanting & craving for porn, but not greater liking. This aligns with the accepted model of addiction - incentive sensitization.
- Porn addicts have greater preference for sexual novelty yet their brains habituated faster to sexual images. Not pre-existing.
- The younger the porn users the greater the cue-induced reactivity in the reward center.
- Higher EEG (P300) readings when porn users were exposed to porn cues (which occurs in other addictions).
- Less desire for sex with a person correlating with greater cue-reactivity to porn images.
- More porn use correlated with lower LPP amplitude when briefly viewing sexual photos: indicates habituation or desensitization.
- Dysfunctional HPA axis and altered brain stress circuits, which occurs in drug addictions (and greater amygdala volume, which is associatewith chronic social stress).
- Epigenetic changes on genes central to the human stress response and closely associated with addiction.
- Higher circulating levels of Tumor Necrosis Factor (TNF) which also occurs in drug abuse and addiction.
Prior to publication of the above studies YBOP claimed that internet porn addiction was real and caused by the same fundamental brain changes as seen in other addictions. We were confident in this claim because basic physiology rests on the fact that drugs do not create anything new or different; they simply increase or decrease existing cellular functions. We already possess the machinery for addiction (mammalian mating/bonding/love circuitry), and for binging (storing calories, mating season). Moreover, years of addiction research have clearly demonstrated that addiction is a single condition, reflected in a typical constellation of signs, symptoms and behaviors (Natural Rewards, Neuroplasticity, and Non-Drug Addictions (2011).
In addition to brain studies on porn users/sex addicts, multiple studies reveal a link between porn use and sexual performance problems, relationship and sexual dissatisfaction, and reduced brain activation to sexual stimuli (see this continuously updated list of studies).
The studies on Internet porn users should come as no surprise because more than 200+ brain studies also confirm that "Internet addicts" develop the same major addiction-related brain changes that occur in drug addictions. Hundreds more assessment-based Internet addiction studies back up what the brain studies found. See our collections:
- Our full collection of recent Internet Addiction Studies.
- List of Internet & Video Game Brain Studies
- Short Summaries of Internet Addiction Research
- Internet Addiction Studies: Containing Excerpts About Porn
- Studies Demonstrating Internet & Porn Use Causing Symptoms & Brain Changes
Internet porn, internet gaming, and social media are now being viewed as separate applications or subcategories of Internet use. An individual can be addicted to Facebook or Internet porn, while not having a "generalized Internet addiction", as explained in this 2015 review of the literature. A 2006 Dutch study found that erotica had the highest addictive potential of all Internet applications.
No wonder. Internet erotica is an extreme version of natural rewards that we're all wired to pursue: sexual arousal and apparent mating opportunities. Today's extreme porn is as unnatural a "natural reinforcer" as today's junk food is. See our article Porn Then and Now: Welcome to Brain Training, and this excellent peer-reviewed article, with a current review of where neuroscience is with respect to Internet porn addiction: Pornography addiction – a supranormal stimulus considered in the context of neuroplasticity (2013).
Recent research on brain changes in response to "highly palatable foods" is revealing evidence of an addiction process. If gambling, gaming, Internet use and food can alter the brain in this way, it would have been amazing to believe that Internet porn alone could not. This is why In 2011, 3000 doctors of the American Society for Addiction Medicine (ASAM) came out with a public statement clarifying that behavioral addictions (sexual, food, gambling) are fundamentally like substance addictions in terms of brain changes. Said ASAM:
"We all have the brain reward circuitry that makes food and sex rewarding. In fact, this is a survival mechanism. In a healthy brain, these rewards have feedback mechanisms for satiety or ‘enough.’ In someone with addiction, the circuitry becomes dysfunctional such that the message to the individual becomes ‘more’, which leads to the pathological pursuit of rewards and/or relief through the use of substances and behaviors."
ASAM specifically addressed sexual behavior addictions:
QUESTION: This new definition of addiction refers to addiction involving gambling, food, and sexual behaviours. Does ASAM really believe that food and sex are addicting?
ANSWER: The new ASAM definition makes a departure from equating addiction with just substance dependence, by describing how addiction is also related to behaviours that are rewarding. ... This definition says that addiction is about functioning and brain circuitry and how the structure and function of the brains of persons with addiction differ from the structure and function of the brains of persons who do not have addiction. ... Food and sexual behaviours and gambling behaviours can be associated with the "pathological pursuit of rewards" described in this new definition of addiction.
Two world-renowned addiction researchers, and ASAM members, gave their opinions years before the new definition:
- The head of the National Institute on Drug Abuse (NIDA) Doctor Nora Volkow, has suggested the agency's name be changed to the "National Institute for Diseases of Addiction," to address behavioral addictions such as pathological gambling, overeating and compulsive pornography use (More Addictions, Less Stigma).
- Addiction researcher, Eric Nestler, has this Q & A on his website, Nestler Labs.
QUESTION: Do these changes occur naturally in your brain without the influence of a drug of abuse?
ANSWER: “It is likely that similar brain changes occur in other pathological conditions which involve the excessive consumption of natural rewards, conditions such as pathological over-eating, pathological gambling, sex addictions, and so on.”
In 2013 the DSM grudgingly acknowledged the preponderance of evidence by creating a new behavioral addiction category. The DSM-5 finally conceded that all addictions appear to involve shared mechanism and brain changes.
“The idea of a non-substance-related addiction may be new to some people, but those of us who are studying the mechanisms of addiction find strong evidence from animal and human research that addiction is a disorder of the brain reward system, and it doesn’t matter whether the system is repeatedly activated by gambling or alcohol or another substance,” said Charles O’Brien, M.D., chair of the DSM-5 Work Group on Substance-Related and Addictive Disorders. “In functional brain imaging—whether with gamblers or drug addicts—when they are showed video or photograph cues associated with their addiction, the same brain areas are activated,” he explained.
Another DSM-5 work-group member (Sexual and Gender Identity Disorders) commenting in this article about Internet porn: Will quitting porn improve your life?
But the kind of definitive research that could explain what happens to the brain while watching porn simply hasn’t been done, says Dr. Richard Krueger, associate clinical professor of psychiatry at Columbia University’s college of physicians and surgeons. Kruger helped revise the sexual disorders section of the latest edition of the psychiatric bible, the Diagnostic and Statistical Manual of Mental Disorders, which doesn’t include sex or porn addiction due to lack of academic evidence that they exist. “The whole notion of what goes on in someone’s brain when they’re sexually excited is just starting to be evaluated,” he says.
He has little doubt porn addiction is real and will eventually garner enough attention to be recognized as a mental illness. But he’s skeptical it has the kind of universal neurological effects that some suggest. Other behaviours such as drinking alcohol or gambling are addictive to only a small minority of the people who engage in them—between one and 10 per cent, Krueger says. “I would argue for the same sort of hit rate with exposure to Internet pornography, that most people would do it and it won’t become a problem.”
Without a doubt, some brains are more sensitive than others to the potentially addictive effects of extreme stimuli. However, it's likely that the more intense our culture's sexual stimuli become, the greater the percentage of users who will show signs of imbalance—even those with fundamentally healthy brains. Also each generation uses more extreme synthetic stimulation than the previous one, and starts earlier with highspeed Internet porn (think smartphones.) Alas, adolescent brains are more vulnerable to addiction and sexual conditioning
We often see healthy guys who develop porn-related erectile dysfunction return to good health simply by avoiding internet porn. This suggests they didn't have other issues that would have accounted for their vulnerability. Not only do those with healthy brains benefit from rebooting (a time-out from all artificial sexual stimuli) and thereafter avoiding extreme stimuli, it's also likely that users with especially sensitive brains, the "canaries in the coal mine," can also ease some of their symptoms by consciously moving toward normal brain sensitivity.