Psychopathic traits linked to brain system

NASHVILLE, March 15 (UPI) -- A U.S. study suggests impulsive anti-social personality traits might be linked to a hypersensitive dopamine brain reward system.

Vanderbilt University scientists say their findings provide the first evidence of differences in the brain's reward system and shed light on a neurochemical vulnerability that might contribute to psychopathic behaviors characterized by a combination of superficial charm, manipulative and anti-social traits, sensation-seeking and impulsivity, blunted empathy and punishment sensitivity and shallow emotional experiences.

The researchers said they found individuals scoring high for psychopathic behaviors -- psychopathy -- had a hypersensitive dopamine response system. Dopamine is a brain system chemical associated with reward and motivation.

"This study helps explain why aggression may be as rewarding for some people as drugs are for others," said Dr. Nora Volkow, director of the National Institute on Drug Abuse. "However, while having an anti-social trait may be a driving factor, it is clearly not sufficient to trigger aggressive behaviors; thus, we need to continue to investigate the other contributors to psychopathy."

The study is reported in the journal Nature Neuroscience.