People diagnosed with schizophrenia are more likely to commit violent crimes than the general population, and their rate of committing violent crimes has been increasing in recent decades, according to a study in The Lancet Psychiatry. An accompanying commentary clarified, however, that the data showed that the dominant risk factors for committing violence did not actually include diagnoses of schizophrenia, and were similar in both people with schizophrenia and in the general population.
Led by University of Oxford psychiatrist Seena Fazel who has co-authored a number of studies linking violence and mental illnesses, the researchers conducted a population cohort study in Sweden of 24,297 patients with schizophrenia-related disorders between 1972 and 2009, and matched them to general population controls and unaffected sibling controls. They examined a variety of outcomes such as convictions for crimes, mortality and suicide.
They found that 10.7% of men and 2.7% of women diagnosed with schizophrenia were convicted of a violent offense within five years of their diagnosis. However, in line with other studies, the researchers found that the dominant risk factors for violence were concomitant substance use problems or histories of violence.
They also found that “the risk of premature death, suicide, and conviction for a violent offense has increased for men and women with schizophrenia in the last 38 years, compared with both the general population, and their unaffected siblings.” In the discussion section of their article, the researchers noted that they did not examine how increasing psychiatric treatment may have influenced people’s likelihood of committing violence.
In a connected Lancet Psychiatry commentary about the study, two University of North Carolina-Chapel Hill School of Medicine psychiatrists stated that, “Several other reasons for outcomes, which were not measured, could explain the higher rates of violence, suicide, and premature mortality in people with psychotic disorders and are not necessarily representative of the disorders themselves. The question remains as to whether schizophrenia could be serving as a proxy for other unmeasured variables such as depression, unemployment, absence of social support, and financial strain, which could mediate the relation between diagnosis and the adverse outcomes studied.”
The authors of the commentary added, “Finally, and importantly, we should remember that, when reporting about the intricate links between schizophrenia and these adverse outcomes, most people with schizophrenia and related disorders are neither violent nor suicidal. Despite the need to ensure people with schizophrenia are provided help to reduce their risks of suicide, violence, or premature death, researchers reporting findings also bear the burden of ensuring that most people with schizophrenia and related disorders, who are not violent, are not left to contend with stigma and discrimination. Policy makers, researchers, and clinicians need to remember the importance of appropriately weighing up the issue of schizophrenia relative to the myriad of other factors that contribute to increased risk of violence and suicide. A focus on the separation of people with schizophrenia from those without the disorder with respect to risk management can contribute to perpetuating a negative public image for people with mental health problems.”
Fazel, Seena, Achim Wolf, Camilla Palm, and Paul Lichtenstein. “Violent Crime, Suicide, and Premature Mortality in Patients with Schizophrenia and Related Disorders: A 38-Year Total Population Study in Sweden.” The Lancet Psychiatry 1, no. 1 (n.d.): 44–54. Accessed June 14, 2015. doi:10.1016/S2215-0366(14)70223-8. (Abstract and full text)
Elbogen, Eric B, and Sally C Johnson. “Violence, Suicide, and All-Cause Mortality.” The Lancet Psychiatry 1, no. 1 (n.d.): 6–8. Accessed June 14, 2015. doi:10.1016/S2215-0366(14)70246-9. (Summary and full text)
The Lancet Psychiatry: Study shows increasing rates of premature death and violent crime in people with schizophrenia since 1970s (The Lancet press release on EurekAlert!, June 3, 2015)