Pervasive developmental disorder, what is this?

It is an out-dated : term for Autistic Spectrum Disorders, which are now " lumped" under one diagnosis in the Diagnostic & Statistical Manual V as Autistic Spectrum Disorder Levels I, II & III, depending on severity. ASD subsumes Asperger Syndrome & PDD-Not Otherwise Specified. Rett Syndrome & Childhood Disintegrative Disorder are no longer included because they differ in cause & clinical course.

PDD: Pervasive developmental disorder is a label/diagnosis given to those with some but not all of the criteria for autistic spectrum disorder. It reflects a less severe disorder. It is used for significant impairment in development of reciprocal social interaction or communication skills or when stereotyped behaviors, interests & activities are present.

A form of autism: Pervasive developmental disorders are now referred to as one classification: autism spectrum disorder. This is a disorder that affects an individual's ability to function well in social situations. This includes trouble with conversation, making and keeping friends, and reading social cues. It can be accompanied by a variety of other behaviors.