A hypersensitive brain reward system may underlie vulnerability to a personality disorder known as psychopathy, according to a brain imaging study by researchers at Vanderbilt University.
The study suggests that the manipulative and aggressive style of behaviors that is common in psychopaths is linked to dopamine, a brain chemical associated with reward and motivation. Because of their heightened response to an anticipated reward, psychopaths could be less fearful about the consequences of their actions, and, thus, more likely to engage in criminal behavior or develop substance use problems.
"Because of these exaggerated dopamine responses, individuals with a latent psychopathic trait may become focused on a chance to get a reward, and less able to shift their attention until they get what they're after," said Joshua Buckholtz, the lead author of the study.
Dr. Nora Volkow, director of the National Institute on Drug Abuse, the organization which funded the study, said, "By linking traits that suggest impulsivity and the potential for anti-social behavior to an overreactive dopamine system, this study helps explain why aggression may be as rewarding for some people as drugs are for others."
The study is published in the current issue of Nature Neuroscience.
