The committee’s concerns are part of a growing chorus of complaints about the increasing use of antipsychotic medicines in children and teenagers. Prescription rates for the drugs have increased more than fivefold for children in the past decade and a half, and doctors now use the drugs to settle outbursts and aggression in children with a wide variety of diagnoses, even though children are especially susceptible to their side effects. A consortium of state Medicaid directors is evaluating the use of the drugs in children on state Medicaid rolls to ensure that they are being properly prescribed. The growing use of the medicines has been driven partly by the sudden popularity of the diagnosis of pediatric bipolar disorder. The leading advocate for the bipolar diagnosis is Dr. Joseph Biederman, a child psychiatrist at Harvard University whose work is under a cloud after a Congressional investigation revealed that he had failed to report to his university at least $1.4 million in outside income from the makers of antipsychotic medicines.