ADHD in children is characterized by inattention, hyperactivity, impulsivity, or a
combination of these symptoms, which compromise basic everyday functions such
as learning to read and making friends.In the absence of biomarkers, diagnostic
criteria focus on behavioral symptoms. Since the same characteristics may be
observed in children and adolescents during typical development, the diagnosis of
ADHD calls for symptoms that are severe, out of proportion to expectations accord-
ing to the child’s age or developmental level, and persistent and for which there are
no appropriate alternative explanations. The disorder is typically diagnosed in
childhood, but affected persons frequently remain symptomatic into adulthood.
ADHD is associated with low rates of high-school graduation and completion of
postsecondary education and poor peer relationships, even when it is appropriately
managed, leading to high economic and social burdens.