Introduction People with major mental disorders are more likely to be violent than other members of the general population. What is contoversial is the influence of the patients’ environnemental violence as regards their aggressive behaviors. The aim of the study was to assess the violence of patients with psychotic disorders regarding the crime rate in the patients’ community. Method We have led a prospective multicentre study in 9 French cities-each of them having different crime rates. Eligible patients were psychotic involuntary patients hospitalized in the cities’acute admission psychiatric wards. During their treatments, any kind of the patients’aggressive behavior has been reported by the OAS (Overt Aggresion Scale). Results From June 2010 to May 2011, 95 patients have been included. Seventy-nine per cent of the patients were violent during their hospitalizations. The patients’violence was mostly verbal (65%). In a bivariate analysis, the patients’violence was significantly associated to different factors: male gender, the patients's violence history, substance abuse, manic or mixed disorder, the symptoms severity measured by the BPRS, the insight degree and the crime rate in the city. In a multivariate analysis, the only significant factors associated with the patients’violence were substance abuse, the symptoms severity and the patients’cities’crime rates. Discussion The results are in accordance with the literature on the risk factors of violent behaviors.The environnemental factor-wich was until now not so much studied-also appears highly associated to this risk. Conclusion These results suggest that the violence within the psychotic patients’environnement could represent a risk of violence during the treatment.