When people with signs of hypersexual disorder look at pornographic images, they don't experience brain wave patterns traditionally associated with addiction, suggests research published online July 19, 2013, in journal Socioaffective Neuroscience and Psychology.

In the recently updated version of its hugely influential mental health handbook, the DSM-5, the American Psychiatric Association included new disorders like binge eating and hoarding, but left out sex addiction.

Mental health professionals don't agree on how to identify, classify or treat sex addiction, formally known as hypersexual disorder, and a new study challenges whether this blurry condition can truly be called an addiction.

When people with signs of hypersexual disorder look at pornographic images, they don't experience brain wave patterns traditionally associated with addiction, the new research suggests. [Hot Stuff? 10 Unusual Sexual Fixations]

Brain on porn

UCLA psychiatry researcher Nicole Prause and colleagues recruited 39 men and 13 women who had trouble controlling their porn viewing habits, with varying degrees of severity. For example, some participants merely wanted to look at less porn, others got in trouble with a spouse, but the more extreme cases resulted in job loss, Prause told LiveScience.

In the study, the participants were shown a battery of images, including a set that merely hinted at sex and others that showed explicit penetration, all mixed in with more pictures not intended to cause sexual arousal, such as a photo of a mutilated body or someone preparing food.

The researchers used electroencephalography (EEG) — a noninvasive technique that uses a skullcap of electrodes to measure brain waves — to look at the neural activity patterns the participants experienced around 300 milliseconds after viewing each image. In previous studies, brain waves in drug addicts surged at this 300-millisecond mark, or p300, when they were shown pictures of drug paraphernalia.

If people with porn problems who were looking at sexually explicit images showed similar p300 activity, this might have suggested that their excessive habits could be likened to drug addiction. But Prause didn't find any such pattern.

There was no rush of p300 brain waves associated with more severe self-reported problems with sexual stimuli. The factor that best predicted a strong response to these pictures was having a high libido, Prause said.

If not addiction, what is it?

Rory Reid, a research psychologist who also works at UCLA but was not involved in the study, told LiveScience that the results do not discount the real problems people with hypersexual disorder experience; rather, they challenge whether an addiction theory is the best explanation of hypersexual behavior. [Hypersex to Hoarding: 7 New Psychological Disorders]

Reid participated in a study last October that described people with hypersexual disorder as having recurrent and intense sexual fantasies, sexual urges and sexual behavior that lasted at least six months, interfered with life, caused distress, and weren't brought on by drugs or another mental disorder. But the behavior of a hypersexual person is not inherently deviant like it is in other disorders such as pedophilia. For that reason, some researchers argue that the diagnosis pathologizes normal sexual urges. Disgraced public figures like Tiger Woods who seek treatment for sex addiction at expensive clinics do little to sway the public that the diagnosis is more than an excuse for cheating on their partner.

Calling hypersexual disorder "sex addiction" may be prematurely labeling it an addictive disorder, which this study highlights. Prause's study wasn't aimed at challenging the legitimacy of problems linked to hypersexual disorder, and there are still many questions left unanswered about how these issues arise. "If not addiction, what's the problem?" she asked.

Future research might show that its characteristics could be more aptly described as an impulsive or compulsive disorder, or a sensitivity to reward, Reid explained. (The brain's reward circuit is responsible for the flood of pleasurable feelings that come with eating ice cream or taking an addictive drug.)

There were other limitations to the new research, such as a restricted sample. An institutional review board prohibited the study's authors from using patients in treatment for sex addiction, fearing that exposure to sexual stimuli might send them into a relapse. Instead, Prause and colleagues used advertisements to recruit people in the Pocatello, Idaho, community who said they were having problems regulating their porn habits. These recruits had similar scores on a Sexual Compulsivity Scale as typical patients with hypersexual problems, the study scientists said.

But hypersexual patients often face problems beyond porn, Reid said. While many do report issues with erotica, some patients can't stop visiting prostitutes or massage parlors; others are plagued with serial affairs. Reid nonetheless commended Prause for raising the bar in the debate over what's behind so-called sex addiction, and he expressed hope that a scientifically tested model for the disorder could help doctors and psychologists better approach it.

"If the field can develop a cohesive theory to explain this phenomenon, then that theory can also help us start to develop treatments for this phenomenon," Reid said.

Prause emphasized that these are the first brain wave results to be published in the field and that the study easily can and should be replicated by other scientists to confirm the findings.

The research was detailed online on July 19 in journal Socioaffective Neuroscience and Psychology.

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