Prescribing antipsychotic drugs to children and adolescents, even for short-term, can cause weight gain and the risk of developing diabetes, researchers have warned.

Antipsychotic drugs are used to treat conditions such as pediatric-onset schizophrenia, and attention deficit hyperactivity disorder (ADHD) in many youths who do not respond to stimulant medications. The findings showed that using these drugs increases body fat and decreases the body's sensitivity to insulin, leading to the development of risk for diabetes.

"It is a challenge for clinicians because we know that antipsychotic medications can produce rapid improvements in disruptive behavioural symptoms in children, but not without serious health consequences," said lead investigator John W. Newcomer, psychiatrist and professor at Florida Atlantic University in US.

But, "if we do treat children with antipsychotics, we have to be diligent in monitoring body weight as well as blood sugar, cholesterol and triglyceride levels and then be prepared to change course if we see adverse medication effects that could increase long-term risk for diabetes, cardiovascular disease and other conditions," added Ginger E. Nicol, Associate Professor at the Washington University in US.

The study, published in the journal JAMA Psychiatry, included data from 144 youths, aged between 6 to 18, who were prescribed antipsychotic drugs to treat disruptive behaviour disorders. Participants were chosen randomly to receive one of three antipsychotics -- aripiprazole, olanzapine or risperidone. The results showed that olanzapine drug produced the largest increase in body fat. After 12 weeks of treatment, the rate of those considered overweight or obese had risen to 46.5 per cent.

"We believe it is time to really hit the brakes on the common first line use of these medications in children with non-psychotic behaviour disorders and to implement more consistent front line use of behavioural treatment options that are available and effective," Newcomer said.