Severe non-lethal violence during psychotic illness

Background: Research about violence in psychosis has mainly considered homicide by people with mental disorder, especially schizophrenia, and violence in groups of psychiatric patients. In this study we examine the characteristics of a sample of offenders with psychotic illness who committed severe non-lethal violent offences. Method: A review of court documents from a consecutive series of cases involving violence resulting in significant injury concluded in the District Court of New South Wales, Australia, in the years 2006 and 2007. Results; Of 661 people found to have committed a severe violent offence, 74 (11%, 95% confidence interval (CI) 9-14%) had a diagnosed psychotic illness. Of these, 16 (22%, 95% CI 12-31%) had never received treatment with antipsychotic medication and could be regarded as being in the first episode of psychosis. Offenders with psychosis were typically non-adherent to treatment, had co-morbid substance use and prior criminal convictions. Positive symptoms of psychotic illness such as hallucinations and delusional beliefs were reported to be present at the time of the offence in most of the cases. Seven of 74 (10%) psychotic offenders were found not guilty on the grounds of mental illness. Conclusions: People with psychotic illness are over-represented among those who commit violent offences resulting in significant injury, confirming the presence of an association between psychosis and severe non-lethal violence. Earlier treatment of first episode psychosis, improving the adherence to treatment of known patients and treatment of co-morbid substance abuse could reduce the incidence of severe violence committed by patients with psychosis.