The researchers, who analyzed data from a national survey of doctors' office visits, found that antipsychotic medications were prescribed to 1,438 per 100,000 children and adolescents in 2002, up from 275 per 100,000 in the two-year period from 1993 to 1995.

The findings augment earlier studies that have documented a sharp rise over the last decade in the prescription of psychiatric drugs for children, including antipsychotics, stimulants like Ritalin and antidepressants, whose sales have slipped only recently. But the new study is the most comprehensive to examine the increase in prescriptions for antipsychotics.

The explosion in the use of drugs, some experts said, can be traced in part to the growing number of children and adolescents whose problems are given psychiatric labels once reserved for adults and to doctors' increasing comfort with a newer generation of drugs for psychosis.