A review of two decades of studies found no evidence that doctors are widely overprescribing stimulants such as Ritalin to hyperactive and inattentive children, the American Medical Association says.

Concerns have emerged in recent years over the rapid increase in the diagnosis and treatment of attention-deficit-hyperactivity disorder, including allegations that children sometimes are given drugs to simply control unwanted behavior in the classroom.But based on a review of studies from 1975 through March 1997, the AMA said there is little evidence of widespread overdiagnosis or misdiagnosis of the disorder, or of widespread overprescription of Ritalin.

A report from its Council on Science and Public Affairs is published in Wednesday's Journal of the American Medical Association.

Dr. Myron Genel, a council member and professor of pediatrics at Yale University School of Medicine, said Tuesday he is unaware of any new studies that would alter the conclusions.

The council said some children are diagnosed after insufficient evaluations and stimulants sometimes are prescribed when alternatives exist, such as behavior therapy and parent training.

But more than 170 studies on more than 6,000 children show that 90 percent with ADHD are noticeably less hyperactive or more attentive when taking one of several stimulants.