JAMA Logo Violent behavior apparently stems from a complicated mix of biological, psychological and social factors. A latest study reveals that men with a history of violent behavior have greater gray matter volume in certain brain areas, while those with a history of substance use disorders have reduced gray matter volume in other brain areas. The discovery presumably has profound implications in the health zone.

This study compared 12 men with and 12 without substance use disorder (SUDs) to 13 non-violent men with SUDs and 14 without. While the first group was recruited from penitentiaries and forensic hospitals, and the second group came from psychiatric outpatient programs and by advertisements and employment agencies. Psychiatrists inspected the participants–all men between 23 and 54 years for mental disorders, psychopathy, aggressive behavior, and impulsivity. Apart from that, subjects also underwent structural magnetic resonance imaging at a university hospital.

The differences in the brains of men were classified in various categories. Those with a history of violence allegedly had a greater volume of gray matter in certain brain areas than non-violent participants, regardless of a history of SUDs. The increases in gray matter volume among violent offenders seemed to be in the mesolimbic areas of the brain. And gray matter decreases in other areas of the brain presumably characterized men with SUDs regardless of a history of violence.

Boris Schiffer, Ph.D., from the University of Duisburg-Essen in Germany, and colleagues mention that in participants with larger gray matter volumes, violent tendencies were linked with higher scores for psychopathy and lifelong aggressiveness. The smaller volumes of gray matter in those with SUDs, on the other hand, were supposedly associated with response inhibition. Additional investigations can be conducted for finding the possible relation between structural abnormalities and specific deficits.

The study is published online by the Archives of General Psychiatry, one of the JAMA/Archives journals.