A growing number of teens and young adults are being prescribed antipsychotics, a new study suggests.

In particular, it appears they’re being used to treat attention deficit and hyperactivity disorder (ADHD) – a condition for which the powerful drugs are not approved.

The percentage of teens using antipsychotics rose from 1.10 percent in 2006 to 1.19 percent in 2010. Use among young adults ages 19 to 24 rose from 0.69 percent to 0.84 percent, the study found.

With roughly 74 million children under 18 in the U.S., these small percentages add up to large numbers of medicated kids.

“Great caution should be exercised in the use of antipsychotics, especially for young children,” said lead study author Dr. Mark Olfson, a research psychiatrist at Columbia University in New York.

Olfson and colleagues analyzed prescription data from 2006, 2008, and 2010 as well as records from 2009 combining pharmacy and medical claims information.

The records covered prescriptions filled at approximately 60 percent of all retail pharmacies in the U.S.

Overall in 2010, approximately 270,000 antipsychotic prescriptions were dispensed to younger children, 2.14 million to older children, 2.80 million to adolescents, and 1.83 million to young adults, the authors write.

Antipsychotic drugs include Abilify (aripiprazole), Risperdal (risperidone), Seroquel (quetiapine), Zyprexa (olanzapine) and others.

For younger children, antipsychotic use declined from 2006 to 2010, the researchers report in JAMA Psychiatry. Prescriptions fell from 0.14 percent to 0.11 percent for kids aged one to six, and from 0.85 percent to 0.80 percent for children aged seven to 12.

This is most likely due to increased efforts to curb antipsychotic use among younger kids over concerns about side effects such as weight gain, high cholesterol and uncertainty about the long-term effects of the drugs on the developing nervous system, Olfson said by email.

Among children 18 and under, the most common reason for antipsychotics was ADHD, the study found. This diagnosis accounted for about 53 percent of prescriptions for younger children, 60 percent for older kids, and 35 percent for teens.

“This is concerning because evidence of antipsychotics’ efficacy for treating a number of behavioral health disorders is lacking,” said Meredith Matone, a research scientist with PolicyLab at the Children’s Hospital of Philadelphia.

Antipsychotics are approved in the U.S. for treatment of psychotic conditions including bipolar disorder and schizophrenia, as well as for easing aggression among cognitively impaired youth, Matone, who wasn’t involved in the study, said by email.

“Increasingly, many youth are receiving these medications to treat behavior problems in the absence of a more severe psychiatric illness,” she said.

Part of this may be due to who is prescribing the drugs, according to an editorial by Dr. Christoph Correll, a psychiatry researcher at the Zucker Hillside Hospital in Glen Oaks, New York and the North Shore-Long Island Jewish Health System.

Out of roughly seven million antipsychotic prescriptions written for children, adolescents and teens in 2010, only 29 to 39 percent came from a child and adolescent psychiatrist, he noted in the editorial.

“I was most surprised by the fact that the majority of youth receiving antipsychotics did not have a mental disorder diagnosis,” Correll told Reuters Health by email.

The study also exposed a gender gap, with prescriptions for boys outpacing girls during elementary, high school and college years.

“The peak use among adolescent boys, who are frequently diagnosed with ADHD and are also treated with stimulants, strongly suggests that antipsychotics are commonly used to treat impulsive aggression and other behavioral symptoms,” Olfson said.

Before parents agree to start their child on antipsychotics to manage aggressive behavior, they should ask about alternative treatments such as anger management, counseling for parents on how to respond to aggression, and other psychosocial options, he said.

“The main takeaway for clinicians and families is that for youth without psychiatric symptoms, alternatives to antipsychotic treatment should be tried whenever possible,” Correll said. “When antipsychotics are used, the lowest risk agents should be used for the shortest time possible.”