BETHESDA, Md., Nov. 13 (UPI) -- Although the brains of children with attention deficit hyperactivity disorder develop more slowly than those of other children, they catch up, a new study says.

   This is welcome news for teachers and psychologists who have feared children who enter school with behavior problems later fall behind their peers, The New York Times reported on Tuesday.

   Scientists from the National Institute of Mental Health and McGill University found the cortices of children with ADHD reach peak thickness on average three years later than children without the disorder. About 3 percent to 5 percent of school-age children are said to be affected by the disorder.

   Dr. Philip Shaw of the National Institute of Mental Health is the author of the report published in Proceedings of the National Academy of Sciences. He said the study might help explain why some children appear to become less fidgety as they mature.

   "The basic sequence of development in the brains of these kids with ADHD was intact, absolutely normal," Shaw told the Times as saying. "I think this is pretty strong evidence we're talking about a delay, and not an abnormal brain."
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