A very small minority of “high-risk” individuals diagnosed with mental illnesses perform acts of violence repeatedly, and their acts of violence are rarely preceded by psychotic experiences, according to a study in Clinical Psychological Science. The findings contradict assertions of advocates for involuntary treatment like E. Fuller Torrey, wrote the authors.
“Advocates of involuntary treatment (Torrey, 2011) assert that untreated psychosis can lead directly to violence,” wrote the University of California, Berkeley-led research team. “This assertion leverages the conclusion of research reviews in the 1990s, which suggested that ‘it is not simply the presence of mental illness that induces violence, but rather the specific presence of delusions and hallucinations’ (Junginger, 1996, p. 92). For example, a patient with persecutory delusions may preemptively strike out to ‘protect’ herself or himself.”
The authors then discussed a variety of more recent studies that have “drawn the strength of these early conclusions into question,” including one study that found that “adherence to antipsychotic medication did not significantly reduce violent behavior” in violent patients with mental illnesses, apparently because their violent tendencies often began in childhood long before they exhibited any mental illness symptoms.
In an effort to investigate further, the researchers decided to focus specifically on the most violent and high-risk individuals that had been identified in the earlier MacArthur Violence Risk Assessment Study.
They defined violence as “acts of battery that resulted in physical injury, sexual assaults, assaultive acts that involved the use of a weapon, and threats made with a weapon in hand.” They then identified 100 patients in the MacArthur study “who were involved in two or more incidents of violence during the year after hospital discharge.” These represented 9% of the MacArthur sample, but accounted for 50% of all the violent acts. The researchers then analyzed the interview data to determine how often psychotic experiences such as delusions or hallucinations preceded these persons’ acts of violence.
“Of the 305 violent incidents in which high-risk patients were involved, only 11.5% of incidents were preceded by psychosis,” the researchers stated. There was also no evidence that the psychotic experiences in this small percentage of cases were causally related to the acts of violence.
The authors concluded that their findings “suggest that effective treatment of psychosis will have negligible direct effects on violence for most patients and important but partial effects for the remainder.”
Skeem, Jennifer, Patrick Kennealy, John Monahan, Jillian Peterson, and Paul Appelbaum. “Psychosis Uncommonly and Inconsistently Precedes Violence Among High-Risk Individuals.” Clinical Psychological Science, April 24, 2015, 2167702615575879. doi:10.1177/2167702615575879. (Abstract)
Psychosis rarely linked to violent crime, study says (University of California, Berkeley press release on HealthDay, June 12, 2015)