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Psychosis rarely, inconsistently precedes violence

Data from the MacArthur Violence Risk Assessment Study suggest that psychosis precedes violent acts some of the time among individuals with repeated involvement with violence, but is uncommon and inconsistent.

“Recent mass shootings in Connecticut, Virginia and Washington, D.C., by individuals who ostensibly have a mental illness have generated tremendous media attention and public concern,” study researcher Jennifer Skeem, PhD, of the University of California, Berkeley, and colleagues wrote in Clinical Psychological Science. “Because these shootings are rare, they are difficult to study systematically and little is known about them.”

Jennifer Skeem

To determine how often and consistently individuals with high risk for violence, or those with repeated involvement with violence, experienced delusions or hallucinations, Skeem and colleagues assessed data from the MacArthur Violence risk Assessment Study. They examined 305 violent incidents associated with 100 former inpatients with repeated violence, which represented 50% of incidents and 9% of the MacArthur study cohort (n = 1,136).

Fifty-three percent of study participants had depression, 15% had schizophrenia or other psychotic disorders and 13% had bipolar disorder.

Of the 305 violent incidents, 11.5% were preceded by psychosis. This proportion was not significantly influenced by patients with particularly high rates of violence, according to researchers.

Among patients who experienced psychosis and repeated violence, psychosis preceded 19.2% of 182 violent incidents.

Analysis indicated there was a “fair” degree of consistency in violence type by patient, however, patients with violence not preceded by psychosis significantly accounted for this effect. Those with psychosis-preceded violent incidents had distinctly different results regarding consistency, according to researchers.

Patients with no psychosis-preceded violence had moderately lower verbal intelligence and modestly greater social deviance vs. patients with a history of both psychosis-preceded violence and no psychosis-preceded violence.

Those who experienced both psychosis-preceded violence and no psychosis-preceded violence had a moderately higher risk for bipolar disorder and a modestly higher risk for schizophrenia or a mental disorder with no substance abuse vs. patients with no psychosis-preceded violence.

“This study has implications for practice with former inpatients with repeated involvement in violence. For those recently or currently experiencing psychosis, symptoms should be monitored and treated — understanding that psychosis immediately precedes about one fifth of this group’s incidents,” Skeem and colleagues wrote. “Similarly, for the few whose violence has been preceded by psychosis in the past year, delusions and hallucinations should be a target for violence prevention — understanding that violence may also have other precipitants.” – by Amanda Oldt

Disclosure: The researchers report no relevant financial disclosures.