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PDD-NOS is the diagnosis given if the individual shows at least one symptom in each of the three core areas. The “Not Otherwise Specified” means that either the doctor did not do an extended evaluation in order to determine if the individual meets one of the other subtypes of Pervasive Developmental Disorder, or although the individual has difficulties in all three areas, any other form of autism spectrum disorder has been ruled out. It is also possible the pediatrician or doctor may not have been sure of the exact subtype, or they may have wanted to see how a young child responds to therapy or intervention before making a definitive diagnosis. Doctors also tend to give this diagnosis to younger children because the very young children may not exhibit some of the traits of autism until they get a little older. You will often see this PDD-NOS diagnosis given to the very young; after being re-evaluated when they are a bit older, the diagnosis may be updated to autism or Asperger’s Syndrome.


Diagnosing very small children is extremely difficult because they can change so much in the first five years of life. For example, it is very hard to evaluate communication during a short doctor appointment if the child isn’t saying anything yet, or is crying a lot. They may be shy, speech delayed, or autistic. So, many pediatricians will simply provide the general category label at that time, and defer a diagnosis until later.

You may have been told that a child has “PDD” (which stands for Pervasive Developmental Disorder) or “ASD”. These are general terms—called umbrella terms—and are not actual diagnoses at this time (although in 2013, the term “ASD” or Autism Spectrum Disorder, will replace all the other labels we use today). These terms are used interchangeably to speak generally about the individual’s profile of skill problems in the three core areas affected by ASD. The common features of these diagnoses are that they all are affected by varying amounts of difficulty with the three core areas: social interaction, communication problems, and unusual or restricted interests and attention. If the individual shows difficulties in each of these areas, the doctor may refer to the child has having “Pervasive Developmental Disorder-Not Otherwise Specified.” It is very difficult to give an exact diagnosis without an extensive evaluation, so many medical professionals just say “ASD” or “PDD” even though that is like a witness describing a hit and run car accident to a police officer by saying “The guy was driving a car” instead of “he was driving a green Honda Civic.”


What is PDD-NOS?