This improved understanding may help to formulate targeted treatment and rehabilitation strategies.

Psychopaths appear to be walking contradictions, exhibiting (sometimes extreme) antisocial behavior while staying on the right side of a diagnosis of "insanity." But as one of the strongest predictors of aggressive and violent behavior, it's important to be able to accurately diagnose psychopathy, especially in the forensic setting.

A new study by US and German researchers has provided a greater understanding of psychopathy, using advanced brain imaging to pinpoint the structural changes that occur in the brains of individuals diagnosed with psychopathy.

The researchers focused on whether different psychopathic traits could be mapped to different brain regions. Psychopathy was measured using the Psychopathy Checklist-Revised (PCL-R), a 20-item scale scored from interview and file information, which has two main parts:

Factor 1: Emotional detachment (e.g., lack of guilt or empathy, superficial charm, manipulativeness).

Factor 2: Antisocial behavior (e.g., deviance from an early age, aggression, impulsivity, irresponsibility, proneness to boredom).

The 20 items are rated on a three-point scale, from zero to two, based on the degree to which the personality or behavior of the subject matches the item description, which then yields a total score. For the present study, the researchers selected 39 males with a PCL-R score of 20 or higher from German forensic institutions, including prisons and secure psychiatric hospitals. They were matched with non-psychopathic control subjects. All participants underwent MRI brain scans. The volumes of different brain regions were analyzed using detailed anatomical atlases of the brain, and statistical models were used to examine the relationships between brain volume and psychopathy scores.