Antipsychotics curb violence in some schizophrenics

By Anthony J. Brown, MD

NEW YORK (Reuters Health) - Some people with schizophrenia become less prone to violence when they take their antipsychotic medications as prescribed by a doctor, but those with a history of antisocial behavior in childhood continue to pose a higher risk even with treatment, research shows. In these individuals, other medications and interventions are likely to be needed.

The research also suggests that the newer, more expensive "atypical" antipsychotics are no better at reducing violent behavior than perphenazine, an antipsychotic agent that has been used for decades. "In fact, one of the newer medications, quetiapine, performed worse than the first-generation drug perphenanize," Dr. Jeffrey W. Swanson, from Duke University School of Medicine in Durham, North Carolina noted in a written statement.

"There are some (schizophrenic) patients with acute psychotic symptoms -- hallucination and delusions -- who become violent," Swanson explained in comments to Reuters Health. "In those patients, treating the symptoms should reduce the risk of violence. This study suggests that is the case."

Swanson said that there are also a large number of people with a history of childhood antisocial conduct. "For patients with this antisocial history, we think adult violent behavior is largely connected to problems that develop earlier in life, before the onset of psychotic illness." Thus, he added, it was not surprising that antipsychotic therapy had little impact on violence in this group.

The findings stem from a study of 1,445 patients with schizophrenia randomized to receive one of five antipsychotic drugs: perphenazine, olanzapine, quetiapine, risperidone, or ziprasidone.

Researchers found that a number of factors contributed to violent acts independently of the person's schizophrenia. In addition to childhood conduct problems, substance abuse, being the victim of past violent acts, poverty and living with others, rather than alone, were all predictors of violent behavior.

"I think the message is that taking antipsychotic medications is likely to reduce the risk of community violence for some, but not all individuals with schizophrenia," Swanson concluded.

"Some people with mental illness may become violent for the same reasons that anyone one else might become violent -- such as having a violent childhood or abusing alcohol or drugs -- and not primarily because they have a mental illness. Clearly, psychiatric medication is never going to fix all the causes of violence in society," Swanson said.

SOURCE: British Journal of Psychiatry, July 2008.