When addicts look at drug-related pictures, their brain activity spikes. A new study investigates what happens when people who see themselves as porn addicts view sexual images. Unusually, their brains show the opposite response — the brain activity decreased.

This study "provides clear evidence that porn does not look like other addictions,” Dr. Nicole Prause, sexual psychophysiologist, neuroscientist, and lead author of the study, told Medical Daily in an email.

Self-described porn addicts often feel they’re out of control and say they don't know how to limit or quit using explicit materials. Viewed from outside, a porn habit seems to share familiar traits all too common with other addictions. But is it the same below the surface — deep inside the brain?

To answer this question, Prause and her colleagues enlisted the help of 122 men and women, with 55 of the volunteers reporting a porn problem. While an EEG recorded their brain activity, the volunteers viewed photographs categorized as pleasant, neutral, and unpleasant, where half of the pleasant photos were erotic.

Observing the volunteers' brain activity via the EEG, the researchers focused on the late positive potential, in particular. This measurement is recorded at the scalp and reflects electrical activity occurring in the visual system and ancient subcortical structures of the brain. When a person pays more attention to a picture — when emotions run high — this type of brain activity increases.

“The size of the late positive potential reflects the intensity of an emotional response,” Dr. Dean Sabatinelli, co-author and an associate professor at University of Georgia, explained in a press release. So, if a gambler were to view pictures of a casino, say, their late positive potential would intensify. The same is true when people addicted to gaming, heroin, nicotine, or cocaine see the fruits of their addiction dangling before their eyes.

Porn, though, does not follow the same pattern. In the current study, those participants who self-identified as porn addicts showed a lower not a higher late positive potential when viewing sexually explicit images.

Citing two reasons why this research is important, Prause first notes the decreased response “means that these porn users do not look like any other addiction; by extension, this means it is not appropriate to call porn addicting from a scientific perspective.” Secondly, she remarks on the study size, which is not only the largest-ever of its kind but also includes more than double the number of participants compared to the most recently published research.

“Larger samples increase confidence in results,” Prause said.

And so the evidence mounts: porn may cause problems for some, but in all likelihood the issue is not based in addiction. The answer lies somewhere else.

Source: Prause N, Steele VR, Staley C, Sabatinelli D, Hajcak G. Modulation of late positive potentials by sexual images in problem users and controls inconsistent with 'porn addiction.' Biological Psychology. 2015.