Study Shows Link Between Violent Acts in Schizophrenia Patients and Substance Abuse
Seena Fazel, M.D., of the University of Oxford in England, and colleagues reported in the May 20 issue of the Journal of the American Medical Association that in their study, the association with violent behavior was weak outside of alcohol or illicit drug abuse. According to the group, these findings counteract the stigma associated with mental illness. They wrote, “The public perception of the dangerousness of psychiatric patients is pervasive and is a key factor in their stigmatization” as a threat to public safety.
Substance abuse is common among schizophrenic patients—30 to 40 percent abuse alcohol and 10 to 15 percent abuse drugs, said Jeffery Lieberman, M.D., of Columbia University and the New York State Psychiatric Institute. “Efforts to prevent people with schizophrenia from using drugs of abuse are very important both to help them stay away from detrimental effects and to protect society from the potential for violence,” he said.
When studying Sweden’s national registries of hospital admissions and criminal convictions from 1973 through 2006, Dr. Fazel and colleagues found that schizophrenia patients were twice as likely to have committed a violent crimes as those in the general population. However, the risk was primarily among patients who abused drugs or alcohol. Among those patients, the rate of violent crime was 27.6 percent (compared with 5.3 percent in the general population). In schizophrenic patients who were not substance abusers (8.5 percent of whom committed at least one violent offense), the odds ratio was only 1.2 when compared with the general population.
The risk of violence in schizophrenic patients has often been chalked up to the delusions and hallucinations that the patients experience as part of the disease, but this study shows that substance abuse is another factor. Because of the role of substance abuse in violence among schizophrenic patients, prevention is key.