Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed conditions in children. For over a hundred years medical literature has been filled with case studies of impulsive boys unable to focus on the task at hand. Research showed many of these boys (and girls) weren't necessarily less bright than other children. They needed to be able to find ways to concentrate. New medications were one way; new study methods were another. No one knows what the causes of ADHD are- in fact, one theory says ADHD isn't a condition at all, just a personality aspect. These links give parents more information on ADHD, and how to help children with ADHD do their best in school and life.
Children and Adults with Attention Deficit Hyperactivity Disorder: http://www.chadd.org/ A non-profit, founded in 1997, to help the families of those with ADHD. It currently has over 16,000 members in 200 locations.