The pervasive developmental disorders (PDDs) are characterized by impairments in socialization, communication, and imagination, and the presence of repetitive and ritualistic behaviors (American Psychiatric Association, DSM-IV, 1994). The PDDs do share some of the positive and negative symptoms of schizophrenia. Autistic disorder is the paradigmatic PDD. Disturbance in social relatedness remains a major defining feature of the disorder. A number of neuroanatomic loci, as well as abnormalities in cerebral lateralization, have been described in the PDD. The most consistent neurotransmitter abnormalities in the PDDs have been found in the serotonin. Since the PDDs are early-onset developmental disorders more readily identifiable in childhood, there is a paucity of information available on the psychopharmacologic treatment of adults with PDD. Currently, the best guide for pharmacologic management of these disorders is empirical treatment of target symptoms. Pharmacologic treatment must be seen in the context of an overall treatment plan.