BACKGROUND: Research has uncovered many characteristics related to violence committed by people with mental illness. However, relatively few studies have focused on understanding the connection between violence and dynamic, malleable variables such as a patient's level of treatment engagement. AIMS: To explore the link between community violence and patients'beliefs about psychiatric treatment benefit. METHOD: A sample of 1011 adults receiving out-patient treatment for a psychiatric disorder in the public mental health systems of five US states were interviewed. RESULTS: Bivariate analyses revealed community violence was inversely related to treatment adherence, perceived treatment need and perceived treatment effectiveness. Multivariate analyses showed these three variables were associated with reduced odds of violent and other aggressive acts. CONCLUSIONS: The results suggest clinical consideration of patients' perceptions of treatment benefit can help enhance violence risk assessment in psychiatric practice settings.