1. Health
You can opt-out at any time. Please refer to our privacy policy for contact information.

Discuss in my forum

Atypical Autism or PDD-NOS

By March 23, 2011

When is an autism spectrum disorder NOT an autism spectrum disorder?  In fact, "atypical autism" or Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) IS considered to be an autism spectrum disorder - even though people with PDD-NOS don't fully qualify for a diagnosis such as autistic disorder or Asperger syndrome.

The idea of a catch-all autism-ish diagnosis is certainly confusing...  it took us quite a while after receiving a "PDD-NOS" diagnosis for our son to figure out that the term had anything whatever to do with autism!

Have you been presented with an "atypical autism" or PDD-NOS diagnosis?   Did it make sense to you?

Find out more about Atypical Autism/PDD-NOS

March 23, 2011 at 1:47 pm
(1) barbaraj says:

My nephew did receive the PDD NOS diagnosis at Krieger, after the first diagnosis of MR, and before the diagnosis of autism. He has a slightly above normal IQ, which removed the earlier diagnosis of MR caused by his behaviors not allowing for testing properly when little.
Atypical, heck if I know, our discussion on another thread touched on this, and imo, it does seem there should perhaps be a division between late onset autism and autism present at birth or as a cofactor in other underlying conditions such as downs ,fragile x ,etc.
I looked around a bit in the last hour and found “late onset autism” the one I call regressive, is often associated with a gut brain as yet not understood pattern of strange and interesting biological issues.

Biological assays lend support to the association between measles virus or MMR and autism whereas epidemiologic studies show no association between MMR and autism. Further research is needed to clarify both the mechanisms whereby viral infection early in development may lead to autism and the possible involvement of the MMR vaccine in the development of autism.

Read More: http://informahealthcare.com/doi/abs/10.1080/13550280590900553

Children with autism had 9 species of Clostridium not found in controls, whereas controls yielded only 3 species not found in children with autism…These studies demonstrate significant alterations in the upper and lower intestinal flora of children with late-onset autism and may provide insights into the nature of this disorder.


Recent clinical studies have revealed a high prevalence of gastrointestinal symptoms, inflammation, and dysfunction in children with autism

March 23, 2011 at 6:50 pm
(2) autism says:

Just posted: the IACC is planning to institute studies specifically looking at causes of regressive autism with some of the symptoms you describe. Included in their plan are studies focusing on vaccines, mito disorders and immune issues.

Now all they need is – oh yeah – funding!


March 23, 2011 at 2:09 pm
(3) Sandy says:

It’s pretty difficult to detect autism at birth, especially when part of the criteria is language, rigid/ restricted, and social.

March 23, 2011 at 2:56 pm
(4) Malia says:

My son’s diagnosis is officially PDD-NOS. It is a diagnosis that has “stood” for many years… and it does make logical sense to me.

A diagnosis of “autistic disorder” means that the child meets sufficient criteria in all three areas listed in the DSM (a) language (b) social and (c) repetititive behaviors. A diagnosis of Asperger’s Syndrome essentially means the child meets the criteria for social impairments and repetitive behaviors, but does not meet the criteria for language delays. My son, however, amply met both the language delay criteria and social impairments criteria; but he did not demonstrate significant repetitive behaviors in front of the diagnosing physician. His behaviors, were not better explained by another psychological disorder, such as schizophrenia, OCD, ODD, etc. Therefore, the logical diagnosis was PDD-NOS.

Personally, I had noticed some repetitive behaviors and stereotypies; however, my son did not “demonstrate” these for the diagnosing doctor. If he had, I believe he would have received an “autistic disorder” diagnosis.

The diagnosis at that time did not arbitrarily mean that he was “high functioning.” His language delays and degree of social impairments were significant and the prognosis we were given initially was pessimistic. He initially tested in the MR range. However, this changed as his language developed and it became evident that he was understanding far more than he was able to express.

As I understand the DSM, a child who meets the criteria for language delays and repetitive behaviors, but does not meet the criteria for social impairments, would also most likely be given a diagnosis of PDD-NOS.

In addition, the criteria be present (or at least be believed to have been present) prior to age 3. A child who clearly develops normally beyond age 3 and then regresses would, I believe, be given a diagnosis of “childhood disintigrative disorder.”

April 22, 2011 at 12:18 pm
(5) Debra says:

My son has PDA (PDD-NOS) He seemed to be progessing normally as a baby, except for his terrible stomach cramps, wind and distended stomach. Then before his first birthday, he lost most of his words and suffered from severe outbursts.

How many children in the country are diagnosed with PDD-NOS and where are the schools to help and understand? He is now eight years old and been excluded from three different schools. He is unable to access mainstream schools, or language units due to his extreme behaviour, and autistic specific schools are too autistic. Is anyone interested in setting up a PDD-NOS specific school with me? :-)

The only school willing to take him on was an EBD (emotional behavioural disorder) boarding school in another county.

There must be a solution to this problem.

March 23, 2011 at 4:57 pm
(6) Paul Whiteley says:

Two points: (1) in the UK we generally do not tend to use the PDD-NOS diagnostic term. Instead it is normally ‘autism’ or an ‘autism spectrum disorder, ASD’. The reasoning for this whilst unclear is probably something to do with Lorna Wing’s book ‘The Autistic Spectrum’ published in 1996. Assuming the DSM-V changes come into effect, ASD will consume PDD-NOS as the over-arching diagnosis anyway:
(2) Current ICD-10 diagnostic criteria actually has 2 categories which straddle PDD-NOS: F84.4 Other pervasive developmental disorder and F84.9 Pervasive developmental disorder, unspecified. I have never been too sure what the difference between them is (if any).

March 25, 2011 at 10:32 am
(7) Malia says:

Hi Paul – I believe you’re refering to F84.8 and F84.9 rather than F84.4 and F84.9. These two categories are not described, so it IS difficult to tell just what would be the difference between them. However, the term often used as an alternative to PDD-NOS, “atypical autism,” is described under F84.1. This category does somewhat mirror the DSM-IV criteria for PDD-NOS in that it says it can be used for individuals, such as my son, who had symptoms in only 2 of the 3 areas (ie. language, social, and repetitive). However, it confuses the issue by also indicating that it can only be used if the age of onset is after 3 years of age (which would disqualify my son from this code). In the ICD, there does not appear to be a category to specifically describe a child who has symptoms in only 2 of the 3 areas onsetting before age 3. Presumeably then, he would have been coded under either F84.8 or F84.9.

I agree, the rewriting of the DSM will change all of this, and my son may indeed lose his diagnosis completely as a result.

March 26, 2011 at 1:17 pm
(8) Paul Whiteley says:

Thanks Malia and apologies for the typo on the ICD coding (the usual excuse – I was tired!). The DSM-V proposals are interesting also because as far as I am aware, they are proposing to lose the onset before 3 years criteria, instead to be replaced by onset in “early childhood” (with no chronological age specifically attached). Cathy Lord and colleagues recently published an indication that this indeed might become an actuality with her latest report on the ADI:
One of the final sentences of the abstract reading: “Results support proposals to remove specific age-based criteria in the diagnosis of ASD”.

March 27, 2011 at 12:26 pm
(9) Dee says:

Actually this is a hot topic in the journals right now because of the proposed changes. Some research is supporting real differences.
You can read about it here: http://www.sciencedirect.com/science?_ob=GatewayURL&_origin=IRSSCONTENT&_method=citationSearch&_piikey=S1750946711000328&_version=1&md5=a060a7e92693aec0a969956a532cf2c5

And here http://dx.doi.org/10.1002%2Faur.178

Leave a Comment

Line and paragraph breaks are automatic. Some HTML allowed: <a href="" title="">, <b>, <i>, <strike>

©2014 About.com. All rights reserved.

We comply with the HONcode standard
for trustworthy health
information: verify here.