Antipsychotic drugs are being prescribed to children in increasing amounts, according to a new study.
The University of London's Pharmacy School's study found that in 1992 595 children in Britain were prescribed antipsychotics at a rate of less than four per 10,000 children.
However, by 2005 that figure had soared to 2,917 children at a rate of seven per 10,000, the study's lead author Fariz Rani found.
The study also found most of those drugs that had been prescribed were not officially approved for children, with the most commonly prescribed ones being those to treat autism and hyperactivity.
Side-effects including weight gain and heart trouble have been reported in autistic or hyperactive children treated with antipsychotic drugs and there is little long-term evidence that the drugs are safe, the report's authors claimed.
They said: "This highlights the need for long-term safety investigations and ongoing clinical monitoring, particularly if the prescribing rate of these medicines continues to rise."
One of the most commonly used antipsychotics in the UK is Risperdal, a schizophrenia drug that is sometimes used to treat irritability and aggression in autism. Its side effects include drowsiness and weight gain.
An earlier US study found nearly 45 American children out of 10,000 used the drugs in 2001 up from more than 23 per 10,000 in 1996.
The new study, based on the health records of more than 16,000 children, has been published in the May edition of the journal Paediatrics.