Table of ContentsView AllTable of ContentsWhy the Definition ChangedPDD-NOS vs ASDTraits of Atypical AutismHow This Affects Treatment
Table of ContentsView All
View All
Table of Contents
Why the Definition Changed
PDD-NOS vs ASD
Traits of Atypical Autism
How This Affects Treatment
Atypical autism, also known aspervasive developmental disorder not otherwise specified (PDD-NOS), was a diagnosis previously used to classify children who had some (but not all) of thetraits of autism.The terms have since been phased out as the definition of autism has changed in recent years.
The “Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition” (DSM-5)updated the definition of autism in 2013 to include a broader range of traits that fall under the larger umbrella ofautism spectrum disorder (ASD).
This article explains how and why PDD-NOS was combined into the diagnosis of ASD and what this means to autistic children and adults.
Charly Franklin / Getty Images
How the Definition of Autism and PDD-NOS Evolved
Autism was first classified as its own diagnosis in the DSM-3, published in 1980.Prior to that, children with autism-like behaviors were given a diagnosis ofchildhood schizophrenia.
The DSM-4, published in 1994, divided autism into five separate diagnostic categories. Among these were autistic disorder,Asperger syndrome, and PDD-NOS.
For autism to be diagnosed under the DSM-4, a child had to meet three diagnostic criteria:
For PDD-NOS to be diagnosed, a child only needed to meet two criteria, one of which must be impairments in social interactions. On top of this, schizophrenia,schizotypal personality disorder (STPD), and avoidant personality disorder (APD) had to be ruled out before the diagnosis could be considered definitive.
PDD-NOS, also known as subthreshold autism or atypical autism, was used when some but not all autism traits were present.It suggested a milder form of autism, which some today might refer to as autism with low support needs orhigh-functioning autism(though this term itself is controversial).
What Are Pervasive Developmental Disorders (PDD)?
What Causes Autism?
Changing Definitions: DSM-5 and Autism Spectrum Disorder
When the DSM-5 was released in 2013, the APA made the decision to fold all five autism categories into a single diagnostic category known as autism spectrum disorder (ASD).
This means that PDD-NOS has been folded into the larger category of ASD. ASD is diagnosed based on a broader range of traits and classified based on intensity and the level of support a person needs in everyday life.
Today, there is a single diagnosis of ASD that replaces the different subcategories used in the DSM-4. The DSM-5 criteria are based on difficulties in two specific areas:
Social Communication Skills
Signs of impairment of social communications skills in autistic children include:
Restricted, Repetitive, and Sensory Behaviors or Interests
These are behaviors in which an autistic child has a limited range of focus or interest, and an often obsessive attachment to objects or sensations.
Examples include:
To be diagnosed with ASD, children must have difficulties with both social communications skills and narrowly focused, repetitive, or sensory behaviors. Moreover, they must have had these issues from early childhood.
How Autism Spectrum Disorder Is Diagnosed
Treatment of PDD-NOS vs. ASD
Another way that PDD-NOS stands outside of the current definition of ASD is the way in which mental health professionals address the intensity of the condition. In the past, the treatment of PDD-NOS was largely the same as for Asperger’s syndrome (autism with low support needs) given that both were regarded as “milder” forms of autism.
It is true that people with PDD-NOS often havemilder traitsbut that doesn’t necessarily mean that it is any less disabling. In fact, some people with PDD-NOS faceintense challenges.
As such, the DSM-5 has established three levels of ASD that reflect the amount of support that a person needs irrespective of the exact features of their condition:
Regardless of the category of diagnosis—whether PDD-NOS or ASD—thetreatmentapproach will likely involve behavioral and/or developmental therapy along with speech, occupational, and physical therapies, and social skills classes for older children.
Summary
Pervasive developmental disorder not otherwise specified (PDD-NOS)—also known as atypical autism—is an outdated term used when a child has some autism traits but does not meet the criteria listed in theDiagnostic and Statistical Manual of Mental Disorders, Fourth Edition(DSM-4).
The next edition, or DSM-5, established three levels of ASD to reflect the amount of support that a person needs. Regardless of whether a diagnosis is ASD or the previous PDD-NOS, treatment typically involves a combination of therapies, including behavioral and/or developmental therapies.
What Is the Best Treatment for Autism?
10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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