Association of Schizoid and Schizotypal Personality disorder with violent crimes and homicides in Greek prisons

Dark or disturbed?: Predicting aggression from the Dark Tetrad and schizotypy

Research on the personality foundations of aggression typically implicates either (a) aspects of the so-called "Dark Tetrad" or (b) severe mental disturbance (psychosis). The appearance of psychotic symptoms in general populations is termed schizotypy. We conducted two studies to compare the effects of dark personalities and schizotypy on aggression. Study 1 used standard inventories to investigate the overlap of Dark Tetrad traits with schizotypy in a sample of 977 undergraduates. All tetrad traits except narcissism were positively associated with schizotypy, but only at moderate levels. Study 2 administered the same personality battery to 303 members of an online community sample: Aggression outcomes were measured with both self-reports and a behavioral measure-the Voodoo Doll Task. Regression analyses determined the unique contributions of the five personality variables. Two dark traits-psychopathy and sadism-were strong predictors of self-report aggression. Schizotypy added incrementally to the Dark Tetrad in predicting both self-report and behaviorally measured aggression.