In the new study, about a third of the children who received antipsychotics had behavior disorders, which included attention deficit problems; a third had psychotic symptoms or developmental problems; and another third were suffering from mood disorders. Over all, more than 40 percent of the children were also taking at least one other psychiatric medication.
"We feel the medications are effective in children with bipolar and have some data to show that," said Dr. Melissa DelBello, an associate professor of psychiatry at the University of Cincinnati, who has done several studies of the drugs.
Dr. DelBello said that the field "desperately needs more research" to clarify the effects of the antipsychotic drugs but that many children struggling with bipolar disorder got more symptom relief on these drugs than on others, allowing psychiatrists to cut down on the overall number of medications a child is taking.
Lisa Pedersen of Dallas, the mother of a 17-year-old boy being treated for bipolar disorder, said he was unpredictable, hostile and suicidal before psychiatrists found an effective cocktail of drugs, which includes a daily dose of antipsychotic medication.
"Believe me, I would never choose having him on these meds," Ms. Pedersen said in a telephone interview. "It's not fun watching a child deal with the side effects. But finding the right combination of medicine has made his life worth living."
Yet this process is one of trial and error for many children. Ms. Pedersen said her son had responded badly to the first two antipsychotic drugs he received. And some experts think the way that psychiatric drugs are prescribed is obscuring any understanding of underlying disorders and the optimal treatments.
"If you're going to put children on three or four different drugs, now you've got a potpourri of target symptoms and side effects," said Dr. Julie Magno Zito, an associate professor of pharmacy and medicine at the University of Maryland.
Dr. Zito added, "How do you even know who the kid is anymore?"