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PDD–NOS is sometimes called ‘atypical autism’.


Children who have been diagnosed with pervasive developmental disorder – not otherwise specified (PDD–NOS) can have characteristics like those of autistic disorder and Asperger’s disorder, but these characteristics are usually fewer or less severe.

Changes to diagnosis of autism spectrum disorder

In May 2013, the criteria used to diagnose children with autism spectrum disorder (ASD) changed.

Previously, the Diagnostic and Statistical Manual of Mental Disorders (4th edition) (DSM-IV) categorised children with ASD as having either autistic disorder, Asperger’s disorder or PDD–NOS. The new version of the Manual, DSM-5, combines these three categories into one, which is simply referred to as autism spectrum disorder (ASD).

The information in this article applies only to people who have been diagnosed using DSM-IV criteria. People who have been diagnosed using DSM-IV criteria will not be affected by the DSM-5 changes to diagnosis.

PDD–NOS: what a diagnosis means

For a diagnosis of autism or Asperger’s disorder, a child must have a certain number of characteristics relating to social and communication skills, and also show some repetitive behaviour. When a child has only some of these characteristics, the child might be diagnosed with pervasive developmental disorder – not otherwise specified (PDD–NOS).

A diagnosis of PDD-NOS still means children will need support and early intervention services.

Sometimes a PDD–NOS diagnosis is followed by an autism spectrum disorder diagnosis a few years later. This possibility of a ‘temporary diagnosis’ of PDD–NOS, although not always the case, is a good reason to explore options for services and interventions.

PDD–NOS: common characteristics

Like children with autism or Asperger’s disorder, children with PDD–NOS will find social interaction hard, or show repetitive behaviour. Although children have these difficulties, their social skills are generally better than children with autism or Asperger’s disorder.

What to do next

If you’re concerned about your child’s development, or already have a PDD–NOS diagnosis, the important thing is to get help and support as soon as possible. The sooner children receive intervention services, the more effective these services can be in fostering positive outcomes.

Here are some ideas to help you get started:

Video Finding and starting early intervention for ASD

In this short video, parents talk about finding and starting early intervention for their children with autism spectrum disorder (ASD). They share their experiences with interventions and tests.

As they note, there are many excellent resources and interventions available, but it’s important to choose interventions based on scientific evidence that work for your child.

  • Last updated or reviewed 26-08-2016
  • Acknowledgements

    This article was developed in collaboration with Cheryl Dissanayake and Cherie Green, Olga Tennison Autism Research Centre, La Trobe University.