The researchers speculate that a heightened response to an anticipated reward could make such individuals less fearful about the consequences of their behavior, which, combined with a reduced sensitivity to others' emotions and resistance to learning from mistakes, could lead to the manipulative and aggressive style of behaviors that is common in psychopaths.
The traits analyzed in this study have been previously shown to predict antisocial behavior and substance abuse in both incarcerated and community samples.
"By linking traits that suggest impulsivity and the potential for antisocial behavior to an overreactive dopamine system, this study helps explain why aggression may be as rewarding for some people as drugs are for others," said NIDA Director Dr. Nora Volkow. "However, while having an antisocial 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."
While the Vanderbilt researchers believe they've made an important first step showing that characterizations of psychopathic behavior are closely related to changes in brain activity, they hope to validate their findings with new studies on individuals who have been actually diagnosed as psychopaths.
"The amount of dopamine released was up to four times higher in people with high levels of these traits, compared to those who scored lower on the personality profile," says Joshua Buckholtz, doctoral candidate in neuroscience and the lead author of the study.
"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
|Contact: NIDA Press Team|
NIH/National Institute on Drug Abuse