A national study of violent behavior in persons with schizophrenia

Violent behavior is uncommon, yet problematic, among schizophrenia patients. The complex effects of clinical, interpersonal, and social-environmental risk factors for violence in this population are poorly understood.

To examine the prevalence and correlates of violence among schizophrenia patients living in the community by developing multivariable statistical models to assess the net effects of psychotic symptoms and other risk factors for minor and serious violence.

A total of 1410 schizophrenia patients were clinically assessed and interviewed about violent behavior in the past 6 months. Data comprise baseline assessments of patients enrolled in the National Institute of Mental Health Clinical Antipsychotic Trials of Intervention Effectiveness.

Adult patients diagnosed as having schizophrenia were enrolled from 56 sites in the United States, including academic medical centers and community providers.

Violence was classified at 2 severity levels: minor violence, corresponding to simple assault without injury or weapon use; and serious violence, corresponding to assault resulting in injury or involving use of a lethal weapon, threat with a lethal weapon in hand, or sexual assault. A composite measure of any violence was also analyzed.

The 6-month prevalence of any violence was 19.1%, with 3.6% of participants reporting serious violent behavior. Distinct, but overlapping, sets of risk factors were associated with minor and serious violence. "Positive" psychotic symptoms, such as persecutory ideation, increased the risk of minor and serious violence, while "negative" psychotic symptoms, such as social withdrawal, lowered the risk of serious violence. Minor violence was associated with co-occurring substance abuse and interpersonal and social factors. Serious violence was associated with psychotic and depressive symptoms, childhood conduct problems, and victimization.

Particular clusters of symptoms may increase or decrease violence risk in schizophrenia patients. Violence risk assessment and management in community-based treatment should focus on combinations of clinical and nonclinical risk factors.