MAOB and personality disorder: On the surface, these results may appear at odds with previous findings on the lower platelet MAO-B activity in imprisoned individuals who committed violent crimes [33,34,35], former juvenile delinquents who developed persistent criminality in adulthood [36], violent male prisoners detained for homicide, assault, or robbery [37], and male prisoners with a history of heavy criminality and with personality disorders (paranoid, schizotypal and schizoid, antisocial, borderline, histrionic, and narcissistic) [35].