A condition occurring in 3 to 4 year olds which is characterized by a deterioration, over several months of intellectual, social, and language functioning. Also known as; disintegrative psychosis or Heller's syndrome. This rather rare condition was described many years before autism but has only recently been 'officially' recognized. With CDD children develop a condition which resembles autism but only after a relatively prolonged period of clearly normal development. This condition apparently differs from autism in the pattern of onset, course, and outcome. Although apparently rare the condition probably has frequently been incorrectly diagnosed. The following is prominent with the condition:

•Loss of social skills.
•Loss of bowel and bladder control.
•Loss of expressive or receptive language.
•Loss of motor skills.
•Lack of play.
•Failure to develop peer relationships.
•Impairment in nonverbal behaviors.
•Delay or lack of spoken language.
•Inability to initiate or sustain a conversation.

source: psychnet-uk.com