Interpersonal violence and mental illness: a literature review

There is a perception that people with a mental illness are dangerous. However, there are still arguments in the research literature as to whether the evidence supports this perception. The major aim of this paper is to review the findings of these studies in regard to the risk of violent behaviour in people with mental illness. An additional aim is to give an overview of the risk factors for violence in people with a mental illness. This systematic search of the literature resulted in good evidence that diagnoses such as schizophrenia and personality disorder are associated with an increased risk of violent behaviour. Substance abuse was the risk factor most associated with an increase in the risk of violent behaviour in people with a mental illness. However, there are substantial differences in the methods used in studies of the risk in violence in people with mental illness resulting in a large variability in the estimates of risk. One of the major causes of variation may be due to the different definitions of violence that are used. The need remains, therefore, for a meta-analysis of this literature based on clear definitions of violence in order to get a more accurate estimate of the risk of violence in people with a mental illness.