Monday, January 21, 2013

Goodbye PDD-NOS, hello SCD

Amidst all the furore about the loss of the Asperger syndrome label and the potential drop-off in autism diagnoses, the proposed introduction of a new diagnosis in DSM-5, Social Communication Disorder, (SCD) has been largely overlooked. When, late last year, it was announced that DSM-5 had been ratified, SCD didn't even warrant a mention. However, it's clearly going ahead.

The APA website now hosts a downloadable PDF describing SCD as follows:
SCD is characterized by a persistent difficulty with verbal and nonverbal communication that cannot be explained by low cognitive ability. Symptoms include difficulty in the acquisition and use of spoken and written language as well as problems with inappropriate responses in conversation. The disorder limits effective communication, social relationships, academic achievement, or occupational performance. Symptoms must be present in early childhood even if they are not recognized until later when speech, language, or communication demands exceed abilities.
Further details are provided in an accompanying article in Psychiatric News:
The criteria describe “persistent difficulties in the social use of verbal and nonverbal communication” in four areas: using communication for social purposes such as greeting or exchanging information; changing communication to match context or the needs of the listener; following rules for conversation or storytelling, such as taking turns in conversation; and understanding what is not explicitly stated and nonliteral or ambiguous meanings of language.
This sounds a lot like autism (at least at the "high functioning" end of the spectrum). In fact the main difference between SCD and ASD in DSM-5 is not some subtle distinction in the type of social communication impairment involved but the fact that an ASD diagnosis also requires evidence of repetitive and restricted behaviours:
while autism spectrum disorder (ASD) does encompass communication problems, it also includes restricted, repetitive patterns of behavior, interests or activities and gives equal weight to both communication issues and repetitive behaviors.
As Will Mandy and colleagues have pointed out, many (if not most) kids accurately diagnosed with PDD-NOS conform to this profile. And it seems as though SCD is essentially a rebranding of PDD-NOS.
Because the symptoms described in SCD were not defined in previous editions of DSM, many individuals with such symptoms may have been lumped under the not otherwise specified category of pervasive development disorder.
In Psychiatric News, Sue Swedo from the DSM-5 Neurodevelopmental Work Group says this:
“We believe social communication disorder will capture those children who have in the past been diagnosed with PDD-NOS as a way of drawing attention to the patient’s social communication impairments despite the absence of restrictive interests and repetitive behaviors.”
This is confusing, because the line all along has been that PDD-NOS would be "folded into" ASD. From the same Psychiatric News article:
Possibly the most significant change is... the consolidation of DSM-IV criteria for autism, Asperger’s, childhood disintegrative disorder, and pervasive developmental disorder-not otherwise specific (PDD-NOS)—into one diagnostic category called autism spectrum disorder (ASD).
It also contradicts the APA line that ASD prevalence won't be affected by DSM-5 changes. This is repeated in another new downloadable PDF from the APA website, describing Autism Spectrum Disorder.
The DSM-5 criteria were tested in real-life clinical settings as part of DSM-5 field trials, and analysis from that testing indicated that there will be no significant changes in the prevalence of the disorder.
More recently, the largest and most up-to-date study, published by Huerta, et al... found that DSM-5 criteria identified 91 percent of children with clinical DSM-IV PDD diagnoses, suggesting that most children with DSM-IV PDD diagnoses will retain their diagnosis of ASD using the new criteria. [2]
However, the same article hints at the fact that some people will be re-assigned:
Anyone diagnosed with one of the four pervasive developmental disorders (PDD) from DSM-IV should still meet the criteria for ASD in DSM-5 or another, more accurate DSM-5 diagnosis [italics added]. While DSM does not outline recommended treatment and services for mental disorders, determining an accurate diagnosis is a first step for a clinician in defining a treatment plan for a patient.
The implication is that people who meet these criteria will be better off with an SCD diagnosis than they would have been with an ASD diagnosis. Put another way, people with similar social communication difficulties should receive different treatments depending on whether or not they also have restricted and repetitive behaviours.

Even if this made sense in theory and even if there was evidence to support it, the main problem from a practical viewpoint is that there are currently no services provided for people with an SCD diagnosis - because it doesn't yet exist. PDD-NOS may have been an inelegant and poorly defined diagnosis, but at least in some (not all) places, it actually meant something in terms of access to support. Those battles will all have to be refought. And even if SCD does eventually become recognised, it is classified in DSM-5 as a form of language disorder, completely separate from ASD, so service provision is likely to be at the same level as that for other language disorders (i.e., not good).

One of the main reasons cited for ditching the distinction between PDD-NOS, Asperger's and autism was a study by Cathy Lord and colleagues indicating that the use of these different diagnoses varies widely across different clinics in different states. As these authors admitted, this variability was likely to be driven at least by regional differences in service provision for the different diagnoses (I think I'm right in saying that the main outlier was California where PDD-NOS and Asperger's diagnoses were never given). DSM-5 was supposed to fix that problem but the worry is that it's going to make things a whole lot worse.

A Spanish translation of this article can be found at Autismo Diario.


MSN News article featuring quotes from Fred Volkmar, Temple Grandin, Cathy Lord, and Ari Ne'eman.


  1. I have PDD-NOS*, and while the criteria for SCD definitely describe me, they are not the only thing I have going on.

    I find it annoying that, as we're starting to understand so much more about other aspects of autism --- perceptual and cognitive aspects --- the clinical definitions seem even more fixated on making it about social communication alone.

    *I would probably have Asperger's if I'd been evaluated later; I was seen in either 1989 or 1990, well before the DSM-IV came out.

  2. I have one child dx pdd-nos and one dx Aspergers. Whereas I think the pdd-nos child would easily meet new criteria for ASD I'm not sure about my Aspie, even though she is pretty typical for girls on the 'high functioning' end of the spectrum. So yes, it is confusing. I am incredibly relieved that my kids are both diagnosed and linked in with services. I wouldn't want to be a parent seeking a diagnosis for a high functioning kid in the coming years.

  3. The point about all these diagnoses is that they only only describe a snapshot in time. People change. People on the autistic spectrum change. As they develop better coping strategies. Self taught or otherwise. As an older adult, I was first diagnosed with Asperger Syndrome/High Functioning Autism. This was later changed at a so called "specialist" centre to 'atypical autism' on the ICD-10 scale. which equates to PDD-NOS on the DSM IV. At the time PDD-NOS was generally reserved for children with little communicative skills (retarded?), and for whom autism was thought inappropriate. Which left me in no man's land! There are no treatments/services for adults with ASD, ASC, PDD, Asperger Syndrome, whatever. We will still be left to our own devices. To make sense of, and live in the NT world.

    1. Yes, regardless of the DSM changes, we need a better understanding of what would be the most helpful services for adults, and then take the time to actually make insurance companies cover those services.

  4. sharing a news :-

  5. The more I hear about the new DSM, the less sense it makes.

    Why is it considered such a big deal whether someone with social and communication disabilities also has repetitive behaviors that it merits a totally new label placed in an entirely different family of disorders? Is there any research or clinical evidence that repetitive behaviors even have that much to do with how well a person functions, at any age?

    Also, why is there no category for people with the opposite profile--repetitive behavior, insistence on sameness, and obsessive interests, but no significant social/communication disabilities? Does this population just not exist? Personally I think this describes a decent size chunk of the gifted population--maybe there's just opposition to labeling them as disordered rather than "atypical NT?"

    Thanks for keeping us informed about all the DSM-5 details as they unfold!

  6. It appears that the Chair of the DSM5 neurodevelopmental work group, Susan Swedo, identifies in the linked video from the APA website below that RRB's can be diagnosed from the history of the patient, per the new finalized DSM5 Diagnostic requirements.

    In the video she suggests that the social-communication criterion are lifelong serious impairments, but RRB criterion impairments can be adapted to through time where they are no longer clinically significant impairments.

    Catherine Lord, from the work group, was quoted in an article a little over a month ago, stating that "essentially everyone get's in" per the final revision of the DSM5 and the addition of consideration of the history of the patient in the diagnostic text, for those currently diagnosed.

    I suppose this video may clarify what it is she meant by that statement that was not worded clearly in that article.

    But, the DSM5 concern voiced by several advocacy organizations was not the RRB's, it was the greater mandatory requirements of the Social-Communication Criterion, for those currently diagnosed with Asperger's syndrome.

    This change may actually be more beneficial to some of those currently meeting a diagnosis of PDD-NOS, that may have experienced clinically significant difficulties in RRB's earlier in life, per history of symptoms, that currently meet requirements of a diagnosis of PDD NOS without clinically significant impairments in RRB's.

    So, in short, it appears they are suggesting that a person on the spectrum cannot "outgrow" their Social-Communication impairments but "adaptations" are possible for RRB's, where they no longer present as clinically significant impairments.

  7. You know what would have been cool, Dr. Brock? If my son would have been treated for his major learning disabilities in school. Not looking for a label, I asked for a psychological assessment in which possible learning differences (leading to accommodations in college) would be looked at exclusively. It was hard, because the Psychiatrist wanted to go all Aspergers so bad, he could taste it. Turns out my son is Dysgraphic and Dyscalculaic, the writing and math answers to Dyslexia. Like self-professed dyslexics, he thinks in pictures, and has difficulty expressing himself verbally, coming up with the right words. He was officially diagnosed PDD-NOS 10 years ago.

  8. Here's why PDD/NOS and Asperger Syndrome have been removed as diagnostic categories whether you agree with it or not:

    Asperger's history of over diagnosis

    'As Martha Denckla, a pediatric neurologist at Johns Hopkins University, has lamented, the only Americans in the future who will perhaps not be labeled as having a touch of Asperger syndrome will be politicians and lobbyists. Members of the political establishment may have other kinds of psychopathology; but, unlike the rest of us, they at least cannot be thought of as Aspies'.

  9. So is SCD the replacement for Asperger's?

  10. A bit new to the whole topic but just wondering if there is a nice article on low-functioning autism (as it is often referred in journal articles) that would explain the definition and perhaps the history of the term? Many papers that I've have read have very different views on how to define it..

  11. My son is 5 1/2. He has been in EI since he was a toddler and now has an IEP in Kindergarten. He was assessed at age 4 and found to be not sutistic, but with autistic features. They didn't go with PDD-NOS partially because they knew it would be going away in the next DSM. My sons social issues seem to be related to his communication problems, rather than the other way around. He has some repetitive behaviors, but they are minor and superficial. He is easily redirected and also plays appropriately much of the time. Seeing the "equal weight" clause for repetitive behavior makes me think SCD is the right diagnosis for him. We have considered the earlier version, PLI and that is waht his SLP thinks he has. However, he also has dyspraxia and sensory issues too. I call it PDD-NOS-lite.

    -Another Mom

  12. " And even if SCD does eventually become recognised, it is classified in DSM-5 as a form of language disorder, completely separate from ASD, so service provision is likely to be at the same level as that for other language disorders (i.e., not good)."

    I'm curious as to what you mean by "not good". Do you mean that level of intensity of service for children with language disorders isn't as high as it is for children with ASD? Or something else?