Attention deficit hyperactivity disorder (ADHD) is a relevantly new term for an old disorder. This is a review of research on the disorder of ADHD. History, prevalence statistics, diagnosis trends, medication information, and effects of exercise on the disorder are addressed. The review of research is not comprehensive, but includes the main points throughout the history of the disorder. The disorder is continually being researched and revised, so it is essential to review all current information concerning the disorder.