Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurological condition related, in part, to the brain's chemistry and anatomy. ADHD manifests itself as a persistent pattern of inattention and/or hyperactivity/impulsivity that occurs more frequently and more severely than is typically observed in people at comparable levels of development. These symptoms must occur for at least six months and have been present since before age 7.

ADHD begins in childhood and can persist into adulthood as well. While some children outgrow ADHD, about 60% continue to have symptoms into adulthood.

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), the symptoms of ADHD fall into three categories: Inattention, Hyperactivity/Impulsivity, and a combination of the two.