A neuropsychological approach was used to examine the frontal lobe and right parietal lobe theories of attention deficit hyperactivity disorder (ADHD). Considerable attempts were made to select as pure a group of ADHD boys as possible. The performance of 10-14-year-old ADHD boys (n = 22), both on and off stimulant medication, was compared with the performance of non-ADHD control boys (n = 22) o...