Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS)

If you've been involved with the world of autism for more than a few years, you may be familiar with a disorder called PDD-NOS (pervasive developmental disorder not otherwise specified). You may even have a child who received the PDD-NOS diagnosis. You might have been told that it's a diagnosis that means "on the autism spectrum, but not falling within any of the existing specific categories of autism."

Two children working on their homework together

Cultura / Sigrid Gombert Collection / Riser / Getty Images

Why PDD-NOS No Longer Exists

PDD-NOS was first added to the Diagnostic and Statistical Manual of Mental Disorders (DSM) in 1987, though it wasn't well described:

This category should be used when there is a qualitative impairment in the development of reciprocal social interaction and of verbal and nonverbal communication skills, but the criteria are not met for Autistic Disorder, Schizophrenia, or Schizotypal or Schizoid Personality Disorder. Some people with this diagnosis will exhibit a markedly restricted repertoire of activities and interests, but others will not.

By the year 2000, the DSM listed five disorders that fell under the category of "pervasive developmental disorders" (PDDs). These included autism, Asperger's syndrome, Rett syndrome, fragile X syndrome, and PDD-NOS. 

When the DSM-5 was published in 2013, however, the term PDD-NOS was not included. Most of the people involved felt that it was too broad and poorly understood to be a useful diagnosis. With the DSM-5, most people who once had the PDD-NOS diagnosis were considered to have an "autism spectrum" diagnosis instead.

Symptoms of PDD-NOS

Before 2013 and the DSM-5, many children had some symptoms of one PDD and some symptoms of another, but not enough of any one of the four specific disorders to receive a diagnosis. In other words, while they clearly had social communication delays and other symptoms, they did not have Rett syndrome, fragile X, Asperger's syndrome, or autism. As a result, they received the catch-all diagnosis of PDD-NOS.

Children with PDD-NOS might have mild or severe symptoms. They may have been intelligent or cognitively delayed. They might have been verbal or non-verbal. The only real point in common, therefore, were some but not all of the symptoms of any of the other PDDs. 

On the upside, PDD-NOS did provide a diagnostic option for doctors looking at children who had a range of differences that didn't seem to fit any particular category. On the downside, the category was so general and so vague that it told parents, therapists, and teachers very little. Unlike the now-defunct Asperger's syndrome category, which was another term for "high-functioning autism." PDD-NOS could mean virtually anything.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. King BH, Navot N, Bernier R, Webb SJ. Update on diagnostic classification in autism. Curr Opin Psychiatry. 2014;27(2):105-9. doi:10.1097/YCO.0000000000000040

  2. Michigan Medicine. Autism, autistic spectrum disorders (ASD) and pervasive developmental disorders (PDD). Updated December 2008.

Additional Reading