The pervasive developmental disorders include a group of conditions in which there is impairment in the development of social skills, language and communication, and behavioral repertoire. Children with pervasive developmental disorders often exhibit idiosyncratic intense interest in a narrow range of activities, resist change, and are not appropriately responsive to the social environment. These disorders affect multiple areas of development, manifest early in life, and cause persistent dysfunction. Autistic disorder, the best known of these disorders, is characterized by sustained impairment in comprehending and responding to social cues; aberrant language development and usage; and restricted, stereotypical behavioral patterns. More than two-thirds of children with autistic disorder have mental retardation, although it is not required for the diagnosis.

There are five pervasive developmental disorders: autistic disorder, Rett syndrome, childhood disintegrative disorder, Asperger’s disorder, and pervasive developmental disorder not otherwise specified. Rett syndrome is characterized by normal development for at least 6 months. The deterioration that follows includes stereotyped hand movements, a loss of purposeful motions, diminishing social engagement, poor coordination, and decreasing language use. In childhood disintegrative disorder, development progresses normally for the first 2 years, after which the child shows a loss of previously acquired skills in two or more of the following areas: language use, social responsiveness, play, motor skills, and bladder or bowel control. Asperger’s disorder is a condition in which the child is markedly impaired in social relatedness and shows repetitive and stereotyped patterns of behavior without a delay in language development. In Asperger’s disorder, a child’s cognitive abilities and adaptive skills are normal.

Students should study the questions and answers below for a useful review of these disorders.