Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common childhood psychiatric disorders, affecting 3-5 percent of all children (approximately 2 million American children). Boys are affected more than girls (two to three times more often). Children diagnosed with ADHD often exhibit certain behaviors over a period of time. These behaviors can usually be classified in the following categories: inattention, hyperactivity and impulsivity. Children with this disorder generally can't stay focused on a task, can't sit still, act without thinking and rarely finish anything. Behaviors can fall within one, two or all three of these categories, onset must be prior to age 7 and continue for over six months, and must have a significant impact on the child's daily functioning in at least two areas such as school, home, or in his/her social environment. It is possible that ADHD can continue into adolescence and adulthood. Research has demonstrated that this disorder appears to stem from biological causes rather than environmental ones.
Source: NARSAD, The Brain and Behavior Research Fund. www.narsad.org