Why Was PDD-NOS Removed from the Diagnostic Manual?

Why did the creators of the DSM5 get rid of the PDD-NOS diagnosis?

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In May 2013, the American Psychiatric Association (APA)released the Diagnostic and Statistical Manual of Mental Disorders (DSM) Version 5. The DSM is a manual that organizes behaviors and symptoms into diagnostic groups for the purposes of clinical diagnosis and recommended treatment.

Over time, the DSM has changed radically; the concept of an "autism spectrum" is relatively recent, and major changes to criteria for autism diagnoses will change what we presently think of as the "autism world." The two most significant changes were be the removal of two existing autism spectrum diagnoses - PDD-NOS and Asperger syndrome - from the manual.

What do these changes mean? To find out more about the proposed changes, I contacted the APA and posed a number of questions. After a few weeks, I received responses, most written by Dr. Bryan King of the Neurodevelopmental Disorders work group.

According to Dr. King, the new criteria are a good way to get more specific about individual cases of autism. The criteria are also designed to separate out children whose challenges don't quite meet the criteria for autism. Prior to DSM5, children with "not quite autism" were diagnosed with PDD-NOS -- a part of the autism spectrum.

Says Dr. King:

In the changes proposed in DSM 5, the focus on  behaviors isn't really changing. However, there is a desire to be able to more precisely describe individuals diagnostically than is currently possible with DSM-IV, and in some cases this may involve using more than one diagnosis.For example, by pulling language impairment out of the diagnostic criteria for autism, we will be able to better describe individuals with autism with or without significant language impairment, as opposed to giving them the same diagnosis. Similarly, the DSM-IV prevents the co-diagnoses of ADHD and autism, or of schizophrenia and autism. But we know that these conditions can co-occur, and DSM 5 will allow for this ability to better capture what is at issue for a given individual than merely "autistic disorder"

Furthermore, PDD-NOS does not have associated diagnostic criteria, as it was originally intended to be used only sparingly for children who didn’t meet criteria for autism or Asperger disorder. Because DSM-IV didn’t have a diagnostic category for children with social communication difficulties only, these children were often given a diagnosis of PDD-NOS. This was not equivalent to a diagnosis of autistic disorder, because it encompassed other developmental disorders as well. The new criteria could re-classify children whose deficits are limited to social communication (and who therefore are not part of the autism spectrum), as well as others, by broadening inclusion in the autism spectrum. The new criteria could also provide for more specific and accurate social communication diagnoses, potentially leading to more appropriate treatment.

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