Attention deficit and hyperactivity disorder associates three specific symptoms: an attention deficit disorder, hyperactivity, and impulsiveness. Most often, this trouble induces educational difficulties with learning disabilities, family difficulties due to parents intolerance and a negative esteem of oneself originating from a depressive personal experience. The differential diagnosis essentially lays in mood troubles, anxiety troubles and psychotic troubles which necessitate a careful biography. The specialized neuropsychological explorations show perturbations at the level of the attentionnel processes and cognitive strategies of the child. The etiopathogeny of the trouble is at the heart of present researches which show a cerebral dysfunction affecting the frontostriatal structures more accentuated on the right. However, the majority of researchers are in favour of a multifactorial etiology: neuropsychological, neurochemical, neurophysiological and genetic. The treatment is based on a psychopedagogical intervention and the prescription of psychostimulants. The evolution is generally suitable to adolescence.