Comorbid personality disorders and violent behavior in psychotic patients.

Schizophrenia without any comorbidity confers a modest, but statistically significant elevation of the risk for violence. That risk is considerably increased by comorbid antisocial personality disorder or psychopathy as well as by comorbid substance use disorders. These comorbidities are frequent. Conduct disorder and conduct disorder symptoms elevate the risk for aggressive behavior in patients with schizophrenia. Violence among adults with schizophrenia may follow at least two distinct pathways-one associated with premorbid conditions, including antisocial conduct, and another associated with the acute psychopathology of schizophrenia. Aggressive behavior in bipolar disorder occurs mainly during manic episodes, but it remains elevated in euthymic patients in comparison with controls. The risk of violent behavior is increased by comorbidity with borderline personality disorder, antisocial personality disorder, and substance use disorders. These comorbidities are frequent. Borderline personality disorder and bipolar disorder are related in their phenomenology and response to medication. These two disorders share a tendency to impulsiveness, and impulsive behavior, including impulsive aggression, is particularly expressed when they co-occur.