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Brain Differences May Help Explain Psychopaths’ Behavior

The impulsiveness, poor judgment, and risk-taking behavior of psychopaths may be attributable in part to differences in brain function, a study by RTI International suggests. The study is among the first to examine and compare variations in brain activity between psychopaths and people without the disorder, said Diana H. Fishbein, director of RTI’s Transdisciplinary Behavioral Science Program and the study’s principal investigator.

From RTI International:

Brain Differences May Help Explain Psychopaths’ Behavior, RTI Study Suggests

The impulsiveness, poor judgment, and risk-taking behavior of psychopaths may be attributable in part to differences in brain function, a study by RTI International suggests.

The study is among the first to examine and compare variations in brain activity between psychopaths and people without the disorder, said Diana H. Fishbein, director of RTI’s Transdisciplinary Behavioral Science Program and the study’s principal investigator.

”Psychopaths commit a disproportionate number of serious crimes and tend to be resistant to conventional treatments,” Fishbein said. ”If we can better understand why some people are psychopathic, the information may lead to more effective treatments and, possibly, preventive interventions.”

The findings emerged from a study to better understand brain mechanisms in drug addiction under a contract with the U.S. Army Contracting Agency with $770,000 provided by the Office of National Drug Control Policy’s Counter-drug Technology Assessment Center.

The purpose of the larger initiative stems from its 1996 investment in a positron emission tomography scanner for the National Institute on Drug Abuse’s Intramural Research Program in Baltimore, where the data were gathered from 2000 to 2002. Aware that psychopaths display a high incidence of drug and alcohol abuse, Fishbein and her colleagues at RTI reanalyzed their initial data, focusing on this subgroup.

The researchers began by identifying study candidates using a questionnaire that measures psychopathic characteristics. Those included in this component of the study scored either in the ”primary psychopathy” or non-psychopathy ranges on the questionnaire.

The researchers then examined the brains of 13 psychopaths and 15 non-psychopaths using the scanner while the participants completed two sets of tests on a computer. The computerized tests measured risk-taking tendencies and decision-making ability by presenting participants with choices and asking them to ”gamble” given numbers of points based on the likelihood that their selections would be correct.

Participants could make two choices: choices that were relatively ‘safe’ in that they would result in a small number of points gained if they picked correctly and a small number of points lost if they picked incorrectly; and riskier choices, which provided a greater reward if correct and a greater penalty if wrong.

Risk taking on this task was characterized by choosing the least likely option in pursuit of a greater reward even in the face of a more substantial penalty, Fishbein said.

As the study participants completed the tests, the scanner illuminated and captured images of the levels of neural activity in various brain regions at work.

After controlling for the effects of drugs on brain function, the psychopath group had a tendency to continue to choose higher risk options than non-psychopaths, even after learning the consequences. During task performance, psychopaths showed greater activation than non-psychopaths within the parts of the brain that are sensitive to reward and error-monitoring while the non-psychopaths showed more activity in areas of the brain responsible for impulse control, abstract thinking, goal direction, and social skills than did the non-psychopath group.

Again taking into consideration prior substance abuse, these findings suggest that the way the brain functions in psychopaths while engaging in risky decision making may compromise psychopaths’ ability to restrain themselves when presented with high-risk options, according to Fishbein.

”With additional research, we may be able to pinpoint not only the neurological underpinnings of this disorder, but perhaps also its origins,” she said.

RTI News Media Contacts
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Research Triangle Park, NC 27709-2194




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