Psychology Today
by Marnia Robinson & Gary Wilson
June 25, 2011

Here’s some headline news for anyone who has been trained that Internet porn use is harmless: Physical evidence of addiction processes is showing up in the brains of avid Internet video-gamers. What’s more, use of online erotica has greater potential for becoming compulsive than online gaming according to Dutch researchers.

According to NIDA head Nora Volkow, MD, and her team these three physical changes define addiction: desensitization (numbing of the brain’s pleasure response), sensitization, and hypofrontality. These same brain changes (which are now showing up in Internet addicts) also show up in pathological gamblers and drug abusers.
For example, cocaine use floods the brain’s reward circuitry with dopamine. Nerve cells respond, more or less quickly, by decreasing their responsiveness to dopamine. As a result, some users feel “off” (desensitization). They crave more intense stimulation (tolerance), and tend to neglect interests, stimuli, and behaviors that were once important to them.

At the same time, because their brains have recorded that cocaine use feels good, they grow hypersensitive to anything they associate with cocaine. White powder, the word “snow,” the neighborhood where they smoked, or friends with whom they used will all trigger spurts of high dopamine in the reward circuitry, driving them to use (sensitization). Also, ΔFosB, a protein that helps preserve intense memories and promotes relapse, accumulates in key brain regions. Incidentally, ΔFosB also rises with sexual activity.

If heavy cocaine use continues, the desensitization of the reward circuitry decreases corresponding activity in the frontal lobes of their brains. Now, the users’ abilities to control impulses and make sound choices weaken, and their frontal cortex may atrophy (hypofrontality). Taken together, decreased pleasure response, marked cravings to use, and compromised impulse control fuel the vicious cycle of addiction.

Behavioral addictions

The study of non-drug addictions is still quite new. Yet already experts have uncovered decisive physical evidence that today’s extreme versions of natural rewards can change the brain in ways that drugs do. “Natural rewards” are activities/substances that entice us because they enhanced our ancestors’ survival, or the survival of their genes.

Moreover, it’s not just a tiny minority with pre-existing disorders who are at risk. Normal, healthy brains can also change. Said a healthy 37-year old, “When I first watched porn online at age 35, I felt like I was going to have an orgasm without an erection. That’s how powerful an effect the it had on me.”

So far, here’s the research scorecard. (Dates indicate when brain-scan research turned up evidence of the last of the three key addiction-related brain changes.)

Pathological gambling – studied for 10 years, and added to the upcoming DSM-5 as an addiction (2010)
Food addiction – (2010)
Internet video-gaming addiction – (2011)
Internet porn addiction – still not studied via brain scans

Incidentally, the reason the Internet addiction studies address addiction to gaming, not porn, is that they were done in countries that block access to porn sites—and have for years (China, 2006 and Korea, 2007). Unlike other countries, they don’t have a lot of heavy porn users.

Here are studies showing the three critical, physical changes in the brains of Internet addicts (two just released in June, 2011):

Numbed pleasure response: Reduced Striatal Dopamine D2 Receptors in People With Internet Addiction (2011)

A reduction of striatal D2 dopamine receptors is the main marker for desensitization of the reward circuitry, a hallmark of all addictions. In this study PET scans of men with and without Internet addiction were compared.

“An increasing amount of research has suggested that Internet addiction is associated with abnormalities in the dopaminergic brain system… [In this study] individuals with Internet addiction showed reduced levels of dopamine D2 receptor availability.”

Sensitization: Changes in Cue Induced Prefrontal Cortex Activity with Video Game Play (2010)

In this study, college students played Internet video games for 6 weeks. Measures were done before and after. Those subjects with the highest cravings also had the most changes in their brains that indicate early addiction process. The control group, which played a less stimulating game, had no such brain changes.

“These changes in frontal-lobe activity with extended video-game play may be similar to those observed during the early stages of addiction.”

Hypofrontality: Microstructure Abnormalities in Adolescents with Internet Addiction Disorder. (2011)

In this study, researchers found a 10-20% reduction in frontal cortex gray matter in adolescents with Internet addiction. Research on other addictions has already established that decreases in frontal-lobe gray matter and functioning reduce both impulse control and the ability to foresee consequences.

“The presence of relatively immature cognitive control, makes [adolescence] a time of vulnerability and adjustment, and may lead to a higher incidence of affective disorders and addiction among adolescents. As one of the common mental health problems amongst Chinese adolescents, internet addiction disorder (IAD) is currently becoming more and more serious. … The incidence rate of internet addiction among Chinese urban youths is about 14%. … These results demonstrated that as internet addiction persisted, brain atrophy … was more serious.” (Also see this earlier Chinese study.)

Online porn and video gaming stimulate the brain in comparable ways

Compare these two quotations. Which is about porn addiction and which is about gaming addiction?

We don’t have sex anymore. We don’t go on date nights or anything together. I feel so guilty because I just can’t take it anymore. Ever since 2 weeks into our marriage I was threatening to divorce him.

Three of my friends did realize they had a problem, but 2 of them said they’ve made attempts to quit, and they literally think there’s nothing they can do about it.

Find full article here: http://www.psychologytoday.com/blog/cupids-poisoned-arrow/201106/ominous-news-porn-users-internet-addiction-atrophies-brains