New research shows that drugs commonly used to treat aggressive or violent behavior in intellectually disabled patients are about 14 percent less effective than a placebo. The findings come as a surprise to some in the medical field, since antipsychotic drugs like Haloperidol and Risperidone are routinely used to treat aggression.

The study by experts in Great Britain and Australia found a 79 percent reduction in aggressive behavior in patients taking the placebo, compared to a 65 percent reduction in patients taking the antipsychotic drugs Haloperidol and Risperidone. The findings, researchers said, would most likely apply to all similar medications as well.

Lead author Peter Tyrer noted that while all treatments led to a reduction in aggressive behavior after four weeks, patients taking a placebo saw the greatest decrease.

“Our trial has shown that aggressive challenging behavior in people with intellectual disability decreases whether or not active medication is given,” Tyrer said.

While some may be surprised by the conclusion, Dr. David Harley from the Queensland Centre for Intellectual and Developmental Disability said the findings did not seem unusual to him because antipsychotic drugs like Haloperidol and Risperidone have not been used for the reasons they were created.

“They are being used to treat [aggression] which is not a recognized medical diagnosis,” he said. “We might expect drugs like this to work if the aggression was caused by schizophrenia or psychotic illness.”

Other doctors, like Philip Mitchell, head of the school of psychiatry at the University of NSW, said the study should be a wake-up call to psychiatrists of the limited benefit of drugs like Haloperidol and Risperidone.

“It should hopefully make clinicians and doctors more circumspect about their prescribing practices,” Mitchell said.

Source: Bellinda Kontominas, “Drugs used to treat aggression not working,”Sydney Morning Herald, January 5, 2008.