Chicago ? Soaring numbers of American children are being prescribed anti-psychotic drugs. And in many cases, they’re being prescribed for attention deficit disorder or other behavioral problems for which these medications have not been proven to work, a study found.

The annual number of children prescribed anti-psychotic drugs jumped fivefold between 1995 and 2002, to an estimated 2.5 million, the study said. That is an increase from 8.6 out of every 1,000 children in the mid-1990s to nearly 40 out of 1,000.

But more than half of the prescriptions were for attention deficit and other nonpsychotic conditions, the researchers said.

The findings are worrisome “because it looks like these medications are being used for large numbers of children in a setting where we don’t know if they work,” said lead author Dr. William Cooper, a pediatrician at Vanderbilt Children’s Hospital.

The increasing use of anti-psychotics since the mid-1990s corresponds with the introduction of costly and heavily marketed medications such as Zyprexa and Risperdal. The packaging information for both says their safety and effectiveness in children have not been established.

Anti-psychotics are intended for use against schizophrenia and other psychotic illnesses.

However, attention deficit disorder is sometimes accompanied by temper outbursts and other disruptive behavior. As a result, some doctors prescribe anti-psychotics to these children to calm them – a strategy some doctors and parents say works.

The drugs, which typically cost several dollars per pill, are considered safer than older anti-psychotics – at least in adults – but they still can have serious side effects, including weight gain, elevated cholesterol and diabetes.

Anecdotal evidence suggests similar side effects occur in children, but large-scale studies of youngsters are needed, Cooper said.

The researchers analyzed data on youngsters age 13 on average who were involved in annual national health surveys. The surveys involved prescriptions given during 119,752 doctor visits. The researchers used that data to come up with national estimates.

The study appears in the March-April edition of the journal Ambulatory Pediatrics.