Psychopathy and violent behavior among patients with schizophrenia or schizoaffective disorder

Objective: Although a strong association between violence and psychopathy h as been demonstrated in nonpsychotic forensic populations, the relationship between psychopathy and violence among patients with schizophrenia has not been thoroughly explored. Patients with and without a history of persisten t violent behavior were compared for comorbidity of psychopathy and schizop hrenia or schizoaffective disorder. Methods: Violent and nonviolent patient s were identified through reviews of hospital charts and records of arrests and convictions. The Psychopathy Checklist: Screening Version was administ ered to 51 patients, 26 violent patients and 25 matched nonviolent patients . Analysis of variance was used as the principal statistical method for com paring violent and nonviolent groups. Results: Mean psychopathy scores were higher for violent patients than nonviolent patients. Five of the violent patients (19 percent) had scores exceeding the cutoff for psychopathy, and 13 (50 percent) scored in the possible psychopathic range. All of the nonvi olent patients scored below the cutoff for possible psychopathy Higher psyc hopathy scores were associated with earlier age of onset of illness and mor e arrests for both violent and nonviolent offenses. Conclusions: The comorb idity of schizophrenia and psychopathy was found to be higher among violent patients than among nonviolent patients. Violent patients with schizophren ia who score high on measures of psychopathy may have a personality disorde r that precedes the emergence of psychotic symptoms, or they may constitute a previously unclassified subtype of schizophrenia, characterized by early symptoms of conduct disorder symptoms and persistent violent behavior.