Addiction Research and Articles About Research

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DSM manualsBelow this long intro are many sub-sections containing relevant studies.

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). In light of the latest scientific advances, the criticisms of the sexual-behavior addiction model are unfounded and outdated. 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. 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." 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. (See this page for critiques and analysis of highly questionable and misleading studies)

At this time a handful of 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. Neural Correlates of Sexual Cue Reactivity in Individuals with and without Compulsive Sexual Behaviours (2014) - 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/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) - Findings match those seen in drug addiction.
  4. Novelty, Conditioning and Attentional Bias to Sexual Rewards (2015) - 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.
  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 addiction. Not so. This SPAN Lab study, like #5 below, actually supports the existence of porn addiction. Why? The 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. However, the study had no control group for comparison, which made the findings uninterpretable. In line with the Cambridge studies, this EEG study reported greater cue-reactivity to porn correlated with less desire for partnered sex. Neither finding matched the headlines. Read more.
  7. Modulation of Late Positive Potentials by Sexual Images in Problem Users and Controls Inconsistent with "Porn Addiction" (2015) - Another SPAN Lab EEG study comparing the 2013 subjects from the above study to an actual control group. The results: compared to controls porn addicts had less response to photos of vanilla porn. The lead author, Nicole Prause, claims these results debunk porn addiction, yet these findings align perfectly with Kühn & Gallinat (2014), which found that more porn use correlated with less brain activation in response to pictures of vanilla porn. In other words, "porn addicts" were desensitized and needed greater stimulation than non-addicts. Read more.
  8. HPA axis dysregulation in men with hypersexual disorder (2015) - 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. Increased sensitivity to erotic reward cues in subjects with compulsive sexual behaviors (2015) - This upcoming fMRI study compared reward center activity of controls to compulsive porn users. Compared to controls compulsive porn users had far greater reward center activity and attentional bias when exposed to sexual cues. Both findings align with the two Cambridge studies (above), and the accepted model of addiction - incentive sensitization.
  10. Ventral striatum activity when watching preferred pornographic pictures is correlated with symptoms of Internet pornography addiction (2016) - Finding #1: Reward center activity (ventral striatum) was higher for preferred pornographic pictures. Finding #2: Ventral striatum reactivity correlated with the internet sex addiction score. Both findings indicate sensitization and align with the addiction model. The authors state that the "Neural basis of Internet pornography addiction is comparable to other addictions."
  11. 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."
  12. 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. Compared to controls compulsive porn users had 1) greater conditioned cue-induced activity in the amygdala, while having 2) decreased coupling between the ventral striatum and the prefrontal cortex. Number 1 indicates sensitization, while number 2 indicates hypofronatlity. In addition, 3 of the 20 compulsive porn users suffered from "orgasmic-erection disorder".

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. The younger the porn users the greater the cue-induced reactivity in the reward center.
  10. Higher EEG (P300) readings when porn users were exposed to porn cues (which occurs in other addictions).
  11. Less desire for sex with a person correlating with greater cue-reactivity to porn images.
  12. More porn use correlated with lower LPP amplitude when briefly viewing sexual photos: indicates habituation or desensitization.
  13. Dysfunctional HPA axis which reflects altered brain stress circuits.

The following neuropsychology studies add to the above neurological studies:

  1. Watching Pornographic Pictures on the Internet: Role of Sexual Arousal Ratings and Psychological-Psychiatric Symptoms for Using Internet Sex Sites Excessively (2011)
  2. Enhanced Attentional Bias towards Sexually Explicit Cues in Individuals with and without Compulsive Sexual Behaviours (2014)
  3. Pornographic picture processing interferes with working memory performance (2013)
  4. Sexual Picture Processing Interferes with Decision-Making Under Ambiguity (2013)
  5. Cybersex addiction: Experienced sexual arousal when watching pornography and not real-life sexual contacts makes the difference (2013)
  6. Cybersex addiction in heterosexual female users of internet pornography can be explained by gratification hypothesis (2014)
  7. Empirical Evidence and Theoretical Considerations on Factors Contributing to Cybersex Addiction From a Cognitive Behavioral View (2014)
  8. Implicit associations in cybersex addiction: Adaption of an Implicit Association Test with pornographic pictures. (2015)
  9. Symptoms of cybersex addiction can be linked to both approaching and avoiding pornographic stimuli: results from an analog sample of regular cybersex users (2015)
  10. Getting stuck with pornography? Overuse or neglect of cybersex cues in a multitasking situation is related to symptoms of cybersex addiction (2015)
  11. Sexual Excitability and Dysfunctional Coping Determine Cybersex Addiction in Homosexual Males (2015)
  12. Trading Later Rewards for Current Pleasure: Pornography Consumption and Delay Discounting (2015)

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).

These studies on Internet porn users should come as no surprise because more than 130+ 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:

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". 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.”

A new European Journal of Behavioral Addictions started in 2012. There is also a yearly conference, and cybersex addiction is becoming a more frequent topic.

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.