Autism Spectrum Disorders (ASD) are severe developmental diseases marked by significant impairment in social, behavioral, and communicative functioning. Their prevalence has increased from earlier estimates of 4 to 5 per 10.000 to about 10 per 10.000. Symptoms are age specific. Intellectual development and early psychosocial rehabilitation are the most important prognostic factors. Life expectancy is similar to that of the general population. In adult life, comorbidity with anxiety disorders or depression and aggression toward self and others may appear. The assumption is that ASDs are of neurobiological origin beginning before birth or in very early child development and involve complex genetic factors. The psychopharmacotherapy of autistic disorders involves treating behavioral symptoms