Childhood disintegrative disorder (CDD), also known as Heller syndrome and disintegrative psychosis, is a rare condition characterized by late onset of developmental delays—or severe and sudden reversals—in language (receptive and expressive), social engagement, bowel and bladder, play and motor skills.
[4][12] Some children describe or appear to be reacting to hallucinations, but the most obvious symptom is that skills apparently attained are lost.
[16][17] However, between the ages of two and 10, skills acquired are lost almost completely in at least two of the following six functional areas:[18] Lack of normal function or impairment also occurs in at least two of the following three areas:[19] In her book Thinking in Pictures, Temple Grandin argues that compared to "Kanner's classic autism" and to Asperger syndrome, CDD is characterized with more severe sensory processing disorder but less severe cognitive problems,[20] despite the fact that most children with CDD regress to severe intellectual disability.
[21] She also argues that compared to most autistic individuals, persons with CDD have more severe speech pathology and they usually do not respond well to stimulants.
"[22] CDD, especially in cases of later age of onset, has also been associated with certain other conditions, particularly the following:[11] Loss of language and skills related to social interaction and self-care are serious.