SUDBURY, Mass.--(BUSINESS WIRE)--U.S. researchers discover that the brains of children and teenagers with Attention Deficit Hyperactivity Disorder (ADHD) are three years delayed compared with typically developing children. “What I wouldn’t take away from this study is: ‘Just sit and wait three years and your kid will be OK. We know ADHD is a real problem for children, their families and schools, and it does need treatment,’” says Dr. Philip Shaw of the National Institute of Mental Health (NIMH), lead author of the study.