Brain abnormalities key to understanding violent offenders

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An MRI-based glimpse into the brains of psychopathic patients revealed abnormalities related to learning from consequences and punishment, according to a study published in this month’s The Lancet Psychiatry.

Violent crime, wrote the authors, including Sarah Gregory, PhD, with the Institute of Psychiatry at King’s College London, is committed by a small number of men who display antisocial and aggressive behavior consistently throughout their lives.

“Focusing on responses to punished reversal errors relative to rewarded correct responses, we tested the hypothesis that violent offenders with antisocial personality disorder and psychopathy would show increased activation within the ventromedial prefrontal cortex, caudate, and posterior cingulate cortex to punished reversal errors, as identification of anomalous responding to reinforcement information within such individuals could be useful as a diagnostic biomarker,” the authors wrote.

The study included 12 violent offenders with antisocial personality disorder and psychopathy, 20 violent offenders with antisocial personality disorder but not psychopathy and 18 healthy non-offenders.

While in the scanner, the participants completed tasks that assessed their abilities to adjust behavior when consequences changed from positive to negative.

The violent offenders, they found, were unable to learn from the punishment cues and did not change their behavior in the face of changing contingencies. The researchers found they made poor decisions despite taking longer to make decisions.

“A white-matter diffusion tensor imaging study of the offenders with antisocial personality disorder and psychopathy from this study revealed reduced fractional anisotropy suggestive of reduced axonal integrity and organization in the dorsal cingulum, which links the posterior cingulate cortex to the medial prefrontal cortex,” the authors wrote.  “The findings from this study support the proposition that the representation of reinforcement value is profoundly disturbed in adult men with psychopathy.”

Gregory et al added that behavior issues and the early signals of psychopathy emerge early in life when learning interventions have the possibility of altering brain structure and function. This information would be crucial in developing strategies and programs to prevent violent behavior and crime from developing in children and in adults.

“Diagnostic classification schemes, offender rehabilitation programmes and childhood prevention programmes would benefit from taking account of this mounting evidence,” the authors concluded.