A lifelong developmental disorder characterized by significant loss of social, play, language, and motor skills after the second year of life. Abnormalities in social interaction and communication are similar to autism.
Also on the Autistic spectrum, this disorder is a marked regression in multiple areas of functioning following a period of at least two years of apparently normal development.
A developmental disorder occurring as a result of a brain disease such an encephalitis in childhood. Symptoms include abnormalities of behaviour, progressing to psychosis.