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Does the brain drive psychopaths to steal and plunder?

Individuals with psychopathic personality traits (i.e. Antisocial Personality disorder) are defined by their aggressive and destructive behavior that often involves breaking laws, theft, etc. While the clinical psychology literature has sought to describe the nature and function of antisocial personality disorder, evidence from neuroscience may highlight the internal workings of the disorder. Scientists from Vanderbilt University recently published a study in the Nature Neuroscience journal describing the brain functioning of individuals with antisocial personality traits. While serotonin release has been related to impulsive behavior, a hyperactive mesolimbic dopamine reward system may explain the related aggressive behavior.

For example, rodent studies have shown that dopamine is released during aggressive behavior, dopamine blockers attenuate aggressive behavior, and trait level differences in aggression are correlated to dopamine levels. Although aggression is not the defining component of antisocial individuals, it is a strong behavioral correlate and has predicted antisocial personality outcomes in both incarcerated and community samples. The authors’ hypothesize that antisocial individuals possess a heightened dopamine release system that drives them to pursue behaviorally relevant environmental reinforcers, thus increasing motivation for obtaining rewards (such as money, drugs, etc.).

Increased motivation for these rewards combined with reduced sensitivity in brain regions responsible for detecting the emotions of others and involved in learning aversive outcomes, could lead to the instrumental style of aggression that is common in psychopaths.

Therefore, a hyperactive dopamine system may explain a disregard for others while manipulating and taking advantage of others for their gain. If the brain is to blame for aggression and reward pursuit,  what should therapists do in working with antisocial individuals? Lastly, I have posted a video from a classic psychopath. I think you will enjoy the clip.


1 comment

  1. Very interesting. The article you are referencing is a good read. I'm not that familiar with mouse models of antisocial personality disorder, but I'm sure variations exist that could be neurochemically tested. It would be interesting to see a breakdown of what is causing the heightened dopamine release. There are many potential mechanisms. I have done projects using mutant mice that have a hyporesponsive mesolimbic dopamine system (less active, opposite of hyperesponsive which is proposed in this article). The hyporesponsive mice do not respond behaviorally (will not self-administer) to psychostimulants, and we found that their dopamine systems are preventing these psychostimulants from causing a build up of extracellular dopamine in the nucleus accumbens (which is associated with the rewarding effects of psychostimulants). We found that they have extra-sensitive autoreceptors that prevent excess dopamine release. So antisocial individuals could have some variations within aspects of their mesolimbic dopamine systems, but it seems more likely to me that other neurotransmitters (such as serotonin, GABA, glutamate) are acting either directly or indirectly on the mesolimbic dopamine system causing it to be hyperesponsive. Since other neurotransmitter systems are obviously associated with these traits in other areas of the brain, an influencing interaction seems quite plausible. I don't have time to scour the literature on this, and sorry to bog your post down with my random thoughts, but you bring up good questions. Keep up the interesting blog!

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