Antipsychotic drugs are widely used to blunt aggressive behaviour in people with intellectual disabilities who have no history of mental illness, a UK survey of medical records finds, even though the medicines may not have a calming effect. The finding is worrisome because antipsychotic drugs can cause severe side effects such as obesity or diabetes.

Psychiatry researcher Rory Sheehan and colleagues at University College London studied data from 33,016 people with intellectual disabilities from general-care practices in the United Kingdom over a period of up to 15 years. The researchers found that 71% of 9,135 people who were treated with antipsychotics had never been diagnosed with a severe mental illness, and that the drugs were more likely to be prescribed to those who displayed problematic behaviours.

“We suspected that this would be the case, but we didn’t know the true extent,” Sheehan says.

We should be worried because the rates are high,” says James Harris, a psychiatrist at Johns Hopkins University in Baltimore, Maryland. But he adds that it is hard to determine whether treatment with antipsychotics is appropriate without knowing what other forms of treatment were available to people in the study. It is possible that medication was the only option available or that it was used to dampen a person's behaviour enough that they could participate in therapy or other types of treatment.

Placebo effect
Evidence suggests that the drugs are not effective at treating aggressive and disruptive behaviour, says psychiatrist Peter Tyrer of Imperial College London. In 2008, he and several colleagues gave haloperidol (Haldol), risperidone (Risperdal) or a placebo to people who had intellectual disabilities but no mental illness, and exhibited aggressive behaviour. The drugs were no better at reducing behavioural problems than the placebo. Because the placebo reduced aggressive behaviour by 79%, Tyrer notes, it may be that antipsychotics are so prevalent simply because they seem to have an effect and can be administered by untrained caregivers in an emergency. “It’s impossible to do a psychological intervention at two in the morning,” Tyrer says.  

The popularity of antipsychotics could also be related to their marketing. In 2013, global health-care company Johnson & Johnson paid more than US$2.2 billion to settle a lawsuit charging that it had improperly marketed risperidone, which had been approved for use in schizophrenia, to treat behaviour problems in children, adults with mental disabilities and elderly people with dementia.

This article is reproduced with permission and was first published on September 1, 2015.