The diagnostic category<unk> s <unk> , as opposed to specific developmental disorders (SDD), refers to a group of five disorders characterized by delays in the development of multiple basic functions including socialization and communication. The most commonly known<unk>  is (1) Autism, with the remaining identified as (2) Rett syndrome, (3) Childhood disintegrative disorder, (4) Asperger syndrome, and (5)<unk>  Not Otherwise Specified (or<unk> -NOS).
Parents may note symptoms of<unk>  as early as infancy and typically onset is prior to 3 years of age.<unk>  itself generally does not affect life expectancy.
There is a division among doctors on the use of the term<unk> . Many use the term<unk>  as a short way of saying<unk> NOS. Others use the general category label of<unk>  because they are hesitant to diagnose very young children with a specific type of<unk> , such as autism.  Both approaches contribute to confusion about the term, because the term<unk>  actually refers to a category of disorders and is not a diagnostic label.
Pervasive developmental disorder
Autism spectrum disorder
Developmental disability
High-functioning autism
Developmental coordination disorder
Conduct disorder
Autistic spectrum
Chronic tic disorder