June 2, 2009 The increased risk for violent crime associated with schizophrenia is largely due to the subgroup of patients who are also substance abusers, according to a study in the May 20 issue of the Journal of the American Medical Association.
Seena Fazel, MD, from the University of Oxford, Warneford Hospital, in the United Kingdom, and colleagues report that schizophrenia without substance abuse was associated with a slightly increased rate of violent crime compared with the general population (odds ratio, 1.2), but persons who had schizophrenia with comorbid substance abuse were more than 4 times as likely as the general population to have a violent-crime conviction.
“The other main finding is that there is familial confounding of the relationship between violent crime and schizophrenia, and that occurs through substance abuse,” Dr. Fazel told Medscape Psychiatry. “In other words, unaffected siblings had increased rates of violent crime compared with the general population, and this appeared to be mediated through higher rates of substance abuse than general population controls.”
