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Schizophrenia tied to increased risk of violence perpetration

JAMA Psychiatry
Reuters Health - 15/01/2022 - Individuals with schizophrenia spectrum disorders are more likely to perpetrate violence than their counterparts without these conditions, a systematic review and meta-analysis suggests. 

Researchers examined data from 24 studies that examined violence perpetration among 50,309 individuals with schizophrenia spectrum disorders as compared to a general population cohort of people without these disorders. Violence was identified in these studies through police or government records, self-report or collateral-report, or medical record review; acts of violence included physical assault, sexual offenses, illegal threats or intimidation, and arson. 

Compared to people without schizophrenia spectrum disorders, violence perpetration was significantly more common among both men (pooled odds ratio 4.5) and women (pooled OR 10.2) with schizophrenia and other psychoses, researchers report in JAMA Psychiatry. 

"There is now good evidence that symptoms of schizophrenia spectrum disorders, such as certain abnormal beliefs about being persecuted or about to be attacked, can cause violence," said senior study author Dr. Seena Fazel, a professor of forensic psychiatry at the University of Oxford in the UK. 

Misuse of drugs and alcohol may exacerbate these symptoms, contribute to disinhibition, and cause disruptions to medical care and social support, Dr. Fazel said by email. Other more general symptoms such as impulsivity, mood lability, and disorganized thinking may also contribute to aggression and violence, Dr. Fazel added. 

"All this is underpinned by treatment research that shows strong and consistent effects of antipsychotics in reducing violent outcomes in schizophrenia-spectrum disorders," Dr. Fazel said. 

The absolute risk of violence perpetration among individuals with schizophrenia spectrum disorders was 1 in 20 among women and 1 in 4 among men in the subset of register-based studies that provided data for this analysis. 

Researchers found a significantly elevated risk of perpetration of sexual offenses (OR 5.1) and homicide (OR 17.7), but they didn't have sufficient data to do a pooled analysis of arson perpetration. 

Most of the studies in the analysis relied on register-based violence perpetration outcomes rather than self-reported outcomes, and it's possible that this may introduce confounding based on the differential treatment of individuals with mental illness by law enforcement and court systems, the study team notes. 

Another limitation of the study is that researchers lacked data on the incidence of violence exposure or childhood trauma among individuals with schizophrenia spectrum disorders, and it's possible that experiencing violence as a victim might independently influence the likelihood of violence perpetration. 

Even so, the results underscore the importance of screening for violence perpetration risk as a routine part of mental health services, Dr. Fazel said. 

"This might be one way that treatment and support to reduce risks can be more accurately and consistently offered to those who need it," Dr. Fazel said. 

SOURCE: https://bit.ly/3rjHxkF JAMA Psychiatry, online December 22, 2021. 

By Lisa Rapaport 

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