Psychiatric disorders are often considered the leading cause of violence. This may be due to a stereotype created by media and general opinion.

The Modified Overt Aggression Scale (MOAS) was used to evaluate the severity of aggressive and violent behaviors in 400 patients who attended a post-acute psychiatric service in Milan from 2014 to 2016 and suffered from different psychiatric disorders. The psychopathological clinical picture was evaluated by Clinical Global Impression (CGI). The study also assessed the possible correlation between epidemiologic and sociodemographic factors, clinical variables, and aggression and violence.

Of the total number of subjects, 21.50% showed a MOAS score >0, 11.50% presented mild aggression (0–10 MOAS weighted score), 9% moderate aggression (11–20), and 1% severe aggression (MOAS >20). With respect to violent behaviors, 16% of patients showed a score >0 in one MOAS subscale other than verbal aggression according to violence definition. The severity of clinical picture seemed to be related to higher weighted MOAS score. Multivariate testing of different sociodemographic and clinical variables showed that violence was related to unemployment status, and significantly correlated to compulsory admission (TSO), suicide attempts (TS), and personality disorders, while the severity of clinical psychiatric picture seemed to play a secondary role.

Results have shown that personality disorders and sociodemographic factors, including economic factors, seem to be major determinants of violence among patients diagnosed with mental disorders.