Mass shootings across the United States continue to stun and mystify, and researchers using data from the MacArthur Violence Risk Assessment Study, sought to understand how psychosis may play a role in extreme acts of violence.
The research, published in Clinical Psychological Science suggests that psychosis plays a role in acts of extreme violence, but only on occasion.
Researchers sought to gain greater understanding of the psychological mechanisms involved in violent, high-risk individuals, primarily by focusing on the consistent incidence of psychosis. As noted by primary author Dr. Jennifer Skeem: “if the policy goal is to maximize public safety, then effective risk reduction for these individuals seems a priority.”
The study focused on two central areas among high risk patients: within the group as a whole, do hallucinations or delusions immediately occur before acts of violence and within individuals over time, how consistent is psychosis before violent incidents?
Participants involved 100 patients involved in the MacArthur Violence Risk Assessment Study, a 12 month study of 1,136 patients discharged from three psychiatric hospitals across the U.S. For purposes of this study, 100 participants met the criteria of being involved in multiple violent incidents in the year following hospital discharge and were able to complete a follow-up interview. The most common diagnoses among participants included depression, bipolar depression and schizophrenia/other psychotic disorders. Male participants numbered 58, while female participants numbered 42.
In general, the study concluded that psychosis, from time to time, played a role immediately before violent incidents (12% of 305 incidents). Additionally, as the research team hypothesized, patients who exhibited non-psychosis preceded violence (80% of the sample size) could be distinguished from a smaller “mixture” group (those patients with a mixture of psychosis-preceded and non-psychosis preceded violence; 20% of the sample size) of patients who exhibited a degree of psychosis-preceded violence; there was reasonable consistency in this difference.
Given the research team were interested in factors which may contribute to harm reduction, characteristics between those former patients who exhibited non-psychosis preceded violence and those who exhibited some psychosis-preceded violence, were examined.
Skeem and her research team found that while both groups shared features of antisocial personality disorder, those former patients with no psychosis-preceded violence had reasonably lower verbal intelligence and fairly greater social deviance, arrest frequency, and childhood abuse frequency. On the other hand, those patients in the “mixture group” were reasonably more likely to meet bipolar depression criteria, in addition to modestly meeting the criteria for schizophrenia and or a mental disorder with no substance abuse.
The researchers concluded that psychosis-preceded acts of violence are uncommon, and that intervention efforts to reduce acts of violence should target broader considerations: “For large-scale violence reduction, the focus of programming for individuals with repeated violence may need to encompass factors associated with social deviance, whether patients occasionally engage in acts of violence related to psychosis or not.”