Think about some of the world's most notorious criminals, such as Jesse James, Charles Manson, and Jeffrey Dahmer. What drove these men to commit such evil acts? While the answer is a complex equation of nature and nurture, a recent study reveals clues to how psychopaths' brains are different from the rest of us.
A putative definition of antisocial personality disorder states that is “a mental health condition in which a person has a long-term pattern of manipulating, exploiting, or violating the rights of others. This behavior is often criminal.” Its causes are unknown. However, research shows that both genes and the environment play roles. Some contributing factors include, for example, child abuse and/or having an antisocial or alcoholic parent. In addition, considerably more men than women have the disorder — it is also common among prisoners.
Building on previous research that has found differences in brain structure between antisocial and healthy people, Kaja Bertsch of the University of Heidelberg recently led the first study that compared two groups of offenders with antisocial personality disorder. The first group was men with antisocial people who also had borderline personality disorder — but were low on the psychopathic traits. The second group was antisocial men who were high on psychopathic traits. The authors reasoned that this was a fruitful comparison because borderline personality disorder or high psychopathic traits co-occur with equal levels of frequency among antisocial offenders.
What are people with antisocial personality actually like? Typically, antisocial offenders with borderline personality disorder are emotionally reactive, unable to regulate emotions, bereft of cognitive empathy (knowing how another person feels), rageful, and reactively aggressive. By contrast, antisocial offenders with high psychopathic traits can be characterized as emotionally detached, cognitively empathic, morally problematic, exploitative, and proactively and reactively aggressive.
The investigators took MRI scans of the two groups of antisocial offenders, with the aim of exploring differences in the cerebral structure of their brains. All offenders had been convicted for capital, violent crimes (including severe bodily injury such as murder, manslaughter, robbery, or rape) from high-security forensic facilities and penal institutions and were formally diagnosed with antisocial personality disorder. There was also a comparison group of healthy men.
What did the researchers find? The antisocial offenders with borderline personality disorder had alterations in the orbitofrontal and ventromedial prefrontal cortex regions, which are involved in emotion regulation and reactive aggression; there were also differences in the temporal pole, which is involved in the interpretation of other peoples’ motives. By contrast, the antisocial offenders with high psychopathic traits showed reduced volume mostly in midline cortical areas, which are involved in the processing of self-referential information and self reflection (i.e., dorsomedial prefrontal cortex, posterior cingulate/precuneus) and recognizing emotions of others (postcentral gyrus). According to the authors, these findings could reflect neural correlates of the psychopath's hallmark features: callousness and moral bankruptcy
The authors note that their results must be replicated in larger samples. Still, they say, this inside look into the antisocial brain may yield clues to criminal behavior.
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