Attention Deficit Hyperactivity Disorder Attention Deficit Hyperactivity Disorder (ADHD), once called hyperkinesis or minimal brain dysfunction, is one of the most common mental disorders among children. ADHD often continues into adolescence and adulthood, and can cause a lifetime of frustrated dreams and emotional pain. It affects 3-5 percent of all children, perhaps as many as 2 million American children. Boys are two to three times more likely to be affected than girls are. On the average at least one child in every classroom in the United States needs help for the disorder. Treatment of this disorder usually involves the over