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History of violence, victimization predicts later violence in schizophrenia

Analysis published in American Journal of Psychiatry revealed that history of engaging in injurious violence in the 6 months before baseline assessment and recent violent victimization were the most powerful predictors of later injurious violent behavior in individuals with schizophrenia.

“Only about 10% of people with schizophrenia will engage in violence during their lifetime; however, they are three to four times more likely to act violently compared with the general population, after adjustment for socioeconomic factors,” Alec Buchanan, PhD, MD, from the division of law and psychiatry, Yale School of Medicine, and colleagues wrote. “Research has not yet clarified whether and to what extent the symptoms and signs of schizophrenia, which often fluctuate in severity, are themselves risk factors for violent behavior.”

To determine the correlates of violence in schizophrenia, the researchers examined 18-month data from 1,435 individuals with schizophrenia who participated in the NIMH’s Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study.

They measured self-reported injurious and noninjurious violence during 18-month follow-up (dependent variables) as well as participants’ baseline recent injurious/noninjurious violence, demographic and background variables, childhood risk factors, clinical condition, current circumstances, and recent contact with hospitals and prisons (independent variables).

During the 18-month follow-up, 77 people with schizophrenia (5.4%) reported engaging in injurious violence and 119 (8.3%) reported engaging in noninjurious violence, according to the results.

In the multivariable analysis, baseline injurious violence (HR = 4.02; 95% CI, 2.12-7.6), recent violent victimization (HR = 3.52; 95% CI, 1.62-7.64), severity of drug use (HR = 2.93; 95% CI, 1.65-5.18), baseline noninjurious violence (HR = 2.72; 95% CI, 1.45-5.09), childhood sexual abuse (HR = 1.85; 95% CI, 1.12-3.05) and medication nonadherence (HR = 1.39; 95% CI, 1.04-1.86) were significantly correlated with later injurious violence among those with schizophrenia.

Among only participants without injurious violence at baseline, baseline noninjurious violence (HR = 3.02; 95% CI, 1.63-5.58), childhood sexual abuse (HR=2.13; 95% CI, 1.22-3.72), severity of drug use (HR = 1.63; 95% CI, 1.21-2.21) and medication nonadherence (HR = 1.48; 95% CI 1.07-2.04) were correlated with later injurious violence.

Unlike previous longitudinal studies, Buchanan and colleagues found no link between negative or positive symptoms of schizophrenia and injurious violence in their analyses.

“Cross-sectional methods allow the possibility that symptoms follow, rather than precede, violence and the absence of a significant association using a prospective method suggests that symptoms such as delusions are sometimes a consequence, rather than a cause, of violence. One possibility is that such symptoms reflect clinical deterioration under the stress of police and legal involvement,” the researchers wrote. – by Savannah Demko

Disclosure: The authors report no relevant financial disclosures.