More than 759 preschoolers were prescribed anti-psychotic drugs last year and use of these medications in children aged under six has leapt 43 per cent in the past three years.
Figures released by the Department of Health and Ageing show a further 3481 children aged seven to 11 are using the powerful medications, even though psychosis does not usually develop until late adolescence.
"We need an audit of children on anti-psychotic drugs and people should be asked to justify their use," argues child psychiatrist Jon Jureidini from Flinders University, who is head of the department of psychological medicine at the Women's and Children's Hospital in Adelaide.
Experts such as Jureidini claim anti-psychosis drugs are increasingly used to treat childhood autism and behaviour problems, despite the fact their effect on the development of a child's brain has not been properly studied. Risperidone, a drug used in the treatment of schizophrenia and bipolar disorder, is the anti-psychotic medicine most commonly prescribed for two to six-year-olds. In 2009-10, this drug was used by 672 children aged two to six and 3147 children aged seven to 11.
It has been associated with weight gain, metabolic disorder and type 2 diabetes. It also causes unco-ordinated movement and increased risk of hyperglycaemia.
According to Jureidini, such medicines are prescribed to manage difficult behaviour rather than psychosis.
"They are increasingly being promoted as broad-spectrum drugs by key opinion leaders who are saying things that are worrying me about broadening their use beyond psychosis," he tells Weekend Health.
University of NSW senior lecturer in psychiatry Michael Dudley says schizophrenia and bipolar disorder typically develop in late adolescence, adding that it's "very rare" for young children to have such problems.
He suggests anti-psychotics are sometimes used to treat autism or intellectual disabilities in youngsters. Like Jureidini, Dudley says statistics on the use of these drugs by children should be released regularly. "These practices should be open to inspection. We need to make the profession accountable."
Martin Whitely, a Labor state MP in Western Australia who campaigns against the use of drugs to treat attention deficit hyperactivity disorder, goes further, calling for a parliamentary inquiry into the use of a range of mental health drugs on young children.
Juredini says there's some justification for their use in children with unmanageable dangerous behaviour - although but only in a multi-disciplinary setting - as anti-psychotics have a numbing and dampening effect on behaviour.
"[But] my guess is they're being used at a much lower threshold," he says, noting he's treated a few children who had been prescribed the drugs by other doctors. "In my experience it's been a positive thing to take the child off the drugs," he says.
The nation's medicines watchdog, the Therapeutic Goods Administration, which collects data on adverse reactions to medicines, has identified a large jump in the number of deaths, in all age groups, associated with one anti-psychotic drug clozapine.
Eighty-three deaths associated with the drug were reported in 2009 and 60 last year. But in the period January to September this year, 151 deaths were reported.
The TGA says it continues to monitor the adverse-event reports: "The balance between the benefits offered by a medicine and the potential risks associated with its use need to be considered when any medicine is prescribed." Used only in people with severe psychiatric disturbance, clozapine carries the risk of serious side effects, including a reduction in the white blood cell count, which increases the risk of serious infections. Its use is highly controlled.
The Department of Health provided the above figures to the Citizens Committee of Human Rights, an organisation set up by the Church of Scientology to campaign against psychiatric violations of human rights, , but it verified their accuracy at Weekend Health's request.