What is the difference between pervasive developmental delay and autism?

A spectrum: Essentially, the degree and...Well...Pervasiveness of delay. Or, as we generally say in psychiatry, the degree of dysfunction. The problem only becomes a problem when the person having the problem sees the problem as actually being a problem....

None: Its a classification description. Pervasive developmental disorders (pdd) is the overall description of conditions sharing significant social and communication disabilities. "mammal" is a term defining hair bearing animals that nurse their young. Autism is a subset of PDD like human is a subset of mammal. Asperger's is a subset of pdd, as are many other conditions.

"Pervasive Develop-: Mental disorders" is now "autistic spectrum disorders." pdd-not otherwise specified, " used for observable behaviors that fulfill some, but not all, criteria for autism will soon be "social communication disorder" in young kids with deficits in social communication & reciprocity but no stereotypies/ narrow, restricted areas of interest. Autistic disorder is the new diagnosis for all other asd's.