What is ADHD?

Most children (and many adolescents and adults) are inattentive, hyperactive, or impulsive at times. ADHD is characterized by a persistent pattern of inattention, hyperactivity, and/or impulsivity that is present early in life (before age seven), inappropriate in light of the person's developmental level,  and causes significant impairment in two or more contexts (for example, at school or work and at home).

There are three subtypes of ADHD: Predominantly Inattentive Type, Predominantly Hyperactive/Impulsive Type, and Combined Type. Predominantly Inattentive Type is characterized primarily by symptoms of inattention (for example, short attention span, distractibility, difficulty organizing things, forgetfulness). Predominantly Hyperactive/Impulsive Type is characterized primarily by symptoms of hyperactivity and impulsivity (for example, difficulty sitting still or staying seated, talking excessively, blurting out, difficulty waiting his or her turn). Combined Type is characterized by symptoms of both inattention and hyperactivity/impulsivity.

Symptoms of inattention, hyperactivity, and/or impulsivity are often present in other mental disorders (for example, mental retardation, autism and other pervasive developmental disorders [PDD], mood disorders, anxiety disorders), and thus do not necessarily mean that a person has ADHD.