Researchers at the National Institute of Mental Health say they have found further evidence that attention-deficit disorder has a neurobiological basis.
The five-year study, one of the largest of its kind to date, looked at 112 boys, ages 5 to 18, roughly half of whom had been diagnosed with the disorder and half of whom had not. An estimated 3 percent to 10 percent of school-age children are thought to have the disorder, which is characterized by an inability to concentrate and, in many cases, impulsiveness and hyperactivity.
The study results were outlined this month at the national meeting of Children and Adults with Attention Deficit Disorders, a Plantation, Fla.-based advocacy group. The study will be published in an upcoming issue of the American Medical Association’s Archives of General Psychiatry.
Researchers found statistically significant size differences in certain regions of the boys’ brains--regions that control functions such as inhibition and planning. They also found that the boys with add had symmetrical right and left sides of their brains; for the control group, the right side of the brain was larger than the left.
Some of the boys with add had been treated previously with stimulant medication. While the researchers do not believe that the medication caused the differences in the two groups’ brains, they have begun a study of boys who have never used such medication. They are also testing girls ages 5 to 18 to see if the findings hold true across gender lines.
An advocacy group for people with mental retardation has given most states an F for not including children with mental retardation in regular classrooms.
The Arc, based in Arlington, Tex., found that children with mental retardation are six times less likely than other children with disabilities to be educated alongside their nondisabled peers. Only 7.1 percent of children with mental retardation were educated in regular classrooms during the 1992-93 school year.
Federal special-education law requires that students be educated in the “least restrictive environment” possible. The rankings are based on data that states report to the U.S. Department of Education.
Vermont claimed the only B grade, with nearly 75 percent of its mentally retarded students placed in regular classrooms. Of the 50 states and the District of Columbia and Puerto Rico, 35 received an F. No state got an A.
According to the group, Vermont, Texas, Idaho, Montana, and Kentucky ranked as the five most inclusive states, while Florida, Rhode Island, Illinois, the District of Columbia, and New Jersey were at the bottom of the list.
A version of this article appeared in the November 22, 1995 edition of Education Week as Special Education column