Purpose: To prevent violence among persons with psychosis, further knowledge of the correlates and risk factors is needed. These risk factors may vary by nation. Patients and methods: This study examined factors associated with violent assaults in 158 patients with psychosis and in a matched control sample of 158 adults without psychosis in the Czech Republic. Participants completed interviews and questionnaires to confirm diagnoses, report on aggressive behavior, current and past victimization, and substance use. Additional information was collected from collateral informants and clinical files. Multiple regression analyses were conducted to identify factors that were independently associated with committing an assault in past 6 months. Results: The presence of a psychotic disorder was associated with an increased risk of assaults (OR =3.80; 95% CI 2.060-7.014). Additional risk factors in persons with and without psychosis included recent physical victimization (OR =7.09; 95% CI 3.922-12.819), childhood maltreatment (OR =3.15; 95% CI 1.877-5.271), the level of drug use (OR =1.13; 95% CI 1.063-1.197), and the level of alcohol use (OR =1.04; 95% CI 1.000-1.084). Increasing age (OR =0.96; 95% CI 0.942-0.978) and employment (OR =0.30; 95% CI 0.166-0.540) were protective factors. Except for drug use, which appeared to have greater effect on violence in the group without psychosis, there were no major differences between patients and controls in these risk and protective factors. To our knowledge, this is the first published comparison of assault predictors between schizophrenia patients and matched controls. Conclusion: Recent physical victimization was the strongest predictor of assaults. Our findings are consistent with the emerging empirical evidence pointing to the very important role of victimization in eliciting violent behavior by the victims. Some current prediction instruments may underestimate the risk of violent behavior as they take little account of current victimization. Although psychosis per se elevates the risk of violence, other risk and protective factors for violence in persons with psychosis and comparison group are largely similar.

Center for Epidemiological and Clinical Research in Addictions National Institute of Mental Health Klecany Czech Republic

Department of Psychiatry 1st Faculty of Medicine Charles University Prague and General University Hospital Prague Prague Czech Republic

Department of Psychiatry 1st Faculty of Medicine Charles University Prague and General University Hospital Prague Prague Czech Republic 7th Field Hospital Czech Armed Forces Hradec Králové Czech Republic Department of Psychiatry Faculty of Medicine University Hospital in Pilsen Charles University Prague Czech Republic Department of Psychiatry Institute for Postgraduate Medical Education Prague Prague Czech Republic

Department of Psychiatry 1st Faculty of Medicine Charles University Prague and General University Hospital Prague Prague Czech Republic Department of Psychiatry Teaching Hospital Královské Vinohrady Prague Czech Republic

Department of Psychiatry Teaching Hospital Královské Vinohrady Prague Czech Republic Psychiatric Hospital Bohnice Prague Czech Republic

Institut Universitaire en Santé Mentale de Montréal Département de Psychiatrie Université de Montréal Montréal Quebec Canada

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