This study measured the prevalence of self-reported violence and associations with psychiatric morbidity in a national household population, based on a cross-sectional survey in 2000 of 8,397 respondents in Great Britain. Diagnoses were derived from computer-assisted interviews, with self-reported violent behavior over the previous 5 years. The 5-year prevalence of nonlethal violence in Britain was 12% (95% confidence interval: 11, 13). The risk of violence was substantially increased by alcohol dependence (odds ratio=2.72, 95% confidence interval: 1.85, 3.98), drug dependence (odds ratio=2.63, 95% confidence interval: 1.45, 4.74), and antisocial personality disorder (odds ratio=6.12, 95% confidence interval: 3.87, 9.66). Low prevalences of these conditions (7%, 4%, and 4%, respectively) contrasted with their relatively high proportions of attributed risk of violence (23%, 15%, and 15%). Hazardous drinking was associated with 56% of all reported violent incidents. Screening positive for psychosis did not independently increase risk (odds ratio=3.20, 95% confidence interval: 0.35, 29.6). The study concluded that psychiatric morbidity makes a significant public health impact on violence exerted primarily by persons with any personality disorder, substance dependence, and hazardous drinking. Population interventions for violent behavior are appropriate for hazardous drinking as are targeted interventions for substance dependence and antisocial personality disorder. Despite public concern, the risks of violence from persons with severe mental illness were very low.