In this paper we describe the main findings of a review of the empirical studies about the relationship of severe mental illness to violence. Both mental illness and violence are public health emergencies. Violence perpetrated by people with severe mental illness is well known not only by clinicians, but also by family members and people in general, because of the negative influence of the media. The closure of state mental hospitals was followed by increases in rates of arrest among former patients. Because of this clinical, social and cultural background, there is much controversy about the major attitude by individuals with severe mental illness to engage in violence. We made a review in order to explain the relationship of severe mental illness to serious violence. Our review shows a chronological evolution. The findings of the last twenty years show a clear relationship of severe mental illness to serious violence. Only some disorders, i.e. schizophrenia and other psychotic disorders, and some constellations of symptoms are related to serious violence. However, such a relationship may be not causal. Epidemiologic studies are often inadequate and cannot establish a causality relationship. Because of both methodological imperfections and stigmatization, we must use caution in interpreting these findings. A recent body of research is analyzing the causal mechanisms of violence in mental illness. Some factors, e.g. psychotic symptoms, may mediate the relationship of severe mental illness to violence.
