RESEARCH WEEKLY: Severe Mental Illness and Violence, Revisited
By Elizabeth Sinclair Hancq
Violence risk in individuals with severe mental illness can be a divisive topic. On the one hand, advocates and the media respond to violent incidents involving someone with severe mental illness as evidence of the substantial risk for violent acts and need for better treatment access to prevent violence. On the other, advocates proclaim that such associations are stigmatizing and the vast majority of people with serious mental illness are not violent and are, in fact, more likely to be victims of violence than perpetrators. According to the research, both are true.
But as Daniel Whiting and colleagues from the University of Oxford write in new research published in JAMA Psychiatry:
“[F]ailure to acknowledge associations with violence perpetration in turn risks leaving clinical needs unmet in psychiatric services. An accurate and balanced understanding of the nuanced association between mental illness and violence perpetration, development of effective prevention, and balanced communication and contextualization of research evidence may be one approach to reducing stigma.”
The published research by Whiting and colleagues does just that by utilizing one of the most statistically powerful research methods that exists, a systematic review and meta-analysis. A systematic review is a research study that comprehensively examines all peer-reviewed published research on a topic and a meta-analysis combines the data of the examined studies to produce results that have broader implications than just any one study may produce.
Results from a meta-analysis on schizophrenia and violence
In total, the review and meta-analysis included 24 published studies that were conducted in 15 countries over 40 years. A combined 51,309 individuals with schizophrenia were included in the analysis.
The review found an increased risk of violence in individuals with schizophrenia compared to the general population, confirming other studies on the topic. Specifically, the results indicate an increased relative risk and higher absolute risk for perpetrating violence towards others in individuals with schizophrenia and associated psychotic disorders.
The absolute risk of perpetuating violence towards others was higher for men than for women with schizophrenia, one in four compared to one in 20, respectively. Compared to individuals in the general population, the results of the analysis suggest there is an increased risk for homicide and sexual offense perpetration in individuals with schizophrenia but was inconclusive on arson. Consistent with previous findings, the risk is increased in younger males and when there is co-morbid substance misuse present.
The authors discuss the clinical importance of violence prevention in individuals with schizophrenia, especially younger males and those with comorbid substance misuse. “Prevention of violence perpetration should be a target for clinical services that assess and treat individuals with these disorders,” the authors conclude.
The authors were not able to determine the effects of treatment on violence perpetration in individuals with schizophrenia in this study. However, previous research has indicated that some antipsychotic medications, such as clozapine, can reduce violence perpetration. In addition, a population study based in Sweden found that violence risk in individuals with schizophrenia was reduced in individuals in active treatment. Further research is needed to determine if treatment brings rates of violence perpetration down to the general population levels.
While these results confirm that most people with severe mental illness are not violent, they clearly indicate an increased risk for violent behavior in individuals with schizophrenia. Acknowledgement and assessment of these results in clinical settings, further research into causal pathways and treatment effects, and attention to risk of violence at the policy level are essential steps to further address violence risk in individuals with schizophrenia. Addressing the potential effects of stigma toward seeking mental health treatment, rather than the stigma of the dangerousness of individuals with these disorders, may have more of an impact on reducing violence risk.