Pervasive Developmental Disorder – Terminology

PDD is not a new diagnosis, or even a new term. Depending on the person using it, it can be a synonym for Autism, or it can be used to denote “high functioning Autism” or Autism in an otherwise bright child. PDD as a term was coined and became popular in the 60’s and 70’s because certain professionals did not like the term Autism, or perhaps didn’t like applying it to such a broad group of kids and wanted a more “benign” sounding word for the milder end of that spectrum.

Parents are often confused by the letters “NOS” in association with PDD. This stands for “Not otherwise specified” and is clinically MEANINGLESS. It is taken from BILLING MANUALS, not clinical texts or research. For instance, the billing codes manual used by all physicians to submit claims to insurance has one code for “Rheumatoid Arthritis”, another for “Osteoarthritis”, another for “Septic Arthritis”, and one for “Arthritis NOS” which is supposed to be used when the doctor doesn’t know yet which kind of arthritis you have, but he/she does think it’s arthritis of some sort. In practice many docs use the “Arthritis NOS” code for ALL types of arthritis because it simplifies work for their billing staff and the insurance company will pay the claims either way. Well, the way the people who write the billing codes manual “translated” the clinical situation with regard to PDD vs. Autism was to consider “Autism” the more specific diagnosis and “PDD” the equivalent of “NOS”. Silly stuff. PDD means exactly the same thing with or without the “NOS”. Certainly grandma doesn’t go around talking about her “arthritis NOS” so parents shouldn’t talk about “PDD-NOS”, just PDD or Autism.