<unk>  <unk> , also known as Heller's syndrome and<unk>  psychosis, is a rare condition characterized by late onset (>3 years of age) of developmental delays in language, social function, and motor skills. Researchers have not been successful in finding a cause for the disorder.<unk>  has some similarity to autism, but an apparent period of fairly normal development is often noted before a regression in skills or a series of regressions in skills. Many children are already somewhat delayed when the illness becomes apparent, but these delays are not always obvious in young children.
The age at which this regression can occur varies, and can be from age 2-10 with the definition of this onset depending largely on opinion.
Regression can be very sudden, and the child may even voice concern about what is happening, much to the parent's surprise. Some children describe or appear to be reacting to hallucinations, but the most obvious symptom is that skills apparently attained are lost.  This has been described by many writers as a devastating condition, affecting both the family and the individual's future. As is the case with all pervasive developmental disorder categories, there is considerable controversy around the right treatment for<unk> .
The syndrome was originally described by Austrian educator Theodore Heller in 1908, 35 years before Leo Kanner described autism, but it has not been officially recognised until recently. Heller used the name dementia infantilis for the syndrome.
Childhood disintegrative disorder
Chronic tic disorder
Conduct disorder
Autism spectrum disorder
Frontal lobe disorder
Oppositional defiant disorder
Tourette syndrome
Episodic dyscontrol syndrome