Violent behavior is infrequent among individuals with schizophrenia but is clinically important. The purpose of this study was to provide data on the correlates of violence, which may allow better risk assessment and care.
A total of 1,435 individuals with schizophrenia who participated in the National Institute of Mental Health’s Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study and were followed for 18 months were examined. The dependent variables were self-reported injurious and noninjurious violence during follow-up. The independent variables, assessed at study entry, comprised participants’ recent injurious and noninjurious violence, demographic and background variables, childhood risk factors, clinical condition, current circumstances, and recent contact with hospitals and prisons. Proportional hazards models of time to first injurious violence were used to generate bivariable and multivariable hazard ratios for all participants and, separately, for participants with no injurious violence at study entry.
Seventy-seven participants (5.4%) reported engaging in injurious violence during follow-up, and 119 (8.3%) reported engaging in exclusively noninjurious violence. In the multivariable analysis, baseline injurious violence (hazard ratio=4.02), recent violent victimization (hazard ratio=3.52), severity of drug use (hazard ratio=2.93), baseline noninjurious violence (hazard ratio=2.72), childhood sexual abuse (hazard ratio=1.85), and medication nonadherence (hazard ratio=1.39) were associated with future injurious violence. For participants with no history of injurious violence at study entry, baseline noninjurious violence was the strongest predictor (hazard ratio=3.02). Recent violent victimization was no longer a significant correlate. The remaining correlates and the strength of their association with future injurious violence were similar to those for all participants.
This is the first longitudinal multivariable analysis of predictors of injurious violence in a large cohort of patients with schizophrenia followed over 18 months. The results revealed simultaneous strong effects of baseline injurious violence and recent violent victimization on future injurious violent behavior. Among clinical variables, poor medication adherence, but not baseline symptoms of psychosis or depression, significantly predicted injurious violence. Treatment strategies to reduce risk should emphasize medication adherence.