Attention-deficit hyperactivity disorder in children.

Abstract

Attention-deficit hyperactivity disorder has been redefined in the classifications in the International Classification of Disease, 10th revision and Diagnostic and Statistical Manual of Mental Disorders, fourth edition. The definitions are more concordant than their predecessors and reemphasize the distinction between inattentiveness and hyperactivity. The causes and mechanisms are still uncertain, but dietary sugar or aspartame and thyroid dysfunction do not seem to be major factors. Specific subgroups, such as children with comorbid psychologic disorders, tic disorders, or mental handicap, seem to have different origins, natural history, prognoses, and responses to treatment, reflecting the heterogeneous nature of the disorder. Psychostimulant therapy has unquestioned short-term effects on behavior but less certain benefits on long-term psychosocial outcome or on academic performance.