Patients are nearly half as likely to commit a violent crime when they are being treated for psychiatric disorders with antipsychotic medication such as risperidone or clozapine compared to when they are not taking medication, according to a new study The study was announced on May 7, 2014, and was published in the journal The Lancet.
The study also showed that mood-stabilizing drugs such as carbamazepine or lithium are also associated with less violent crime. The reduction is less dramatic, and only occurs in patients with bipolar disorder.
Mood stabilizing and antipsychotic drugs are usually used in mental health disorders such as bipolar disorder, schizophrenia, and related disorders, which affect up to two percent of the general population. Past research has shown that people who are treated with these medications are at a lesser risk of relapse and re-hospitalization for their illness, but there has been little evidence on the drug’s impact on adverse outcomes such as reducing violent behavior.
A team of researchers in the UK and Sweden led by Dr Seena Fazel of Oxford University, UK used Swedish national health registries to analyze psychiatric patients undergoing treatment and criminal convictions. The results showed that more than 80,000 patients (40,937 men and 41,710 women) who were prescribed antipsychotic or mood stabilizing medication from 2006 to 2009.
The findings showed that 2657 (6.5 percent) of men, and 604 (1.4 percent) of women were convicted of a violent crime. When researchers compared data on periods when patients were in treatment to periods when the patients were not taking medication, violent crime decreased by 46 percent in patients taking antipsychotics, and 24 percent in patients who were taking mood stabilizers.
When the two types of medication are combined, the investigators did not find any evidence that the combination created a reduction in violent crime. Among patients who were treated with mood stabilizers, violent crime was only reduced in male patients diagnosed with bipolar disorder. Many patients in the study were also prescribed drugs for other disorders such a substance abuse or depression.
"Patients with psychiatric disorders are at risk of perpetrating violent acts, as well as being victims," said Dr Fazel. "Until now, we have not known whether antipsychotics and mood stabilizers reduce risks of violence. By comparing the same people when they are on medication compared to when they are not, our study provides evidence of potentially substantial reductions in risk of violence, and suggests that violence is to a large extent preventable in patients with psychiatric disorders."
Professor Sheilagh Hodgins of Université de Montréal, Canada, and Karolinska Institutet, Stockholm, Sweden, wrote that this "well-executed study provides a basis for future clinical studies aiming to establish how antipsychotics and mood stabilizers can be used to reduce aggressive behavior. The study illustrates again that de-identified data from national registers that were established for administrative reasons can be used by epidemiologists to identify potential strategies to reduce health-related social problems."