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New Definition of Autism May Exclude Many, Study Suggests

Posted Jan 20 2012 5:42pm

The New York Times reports New Definition of Autism May Exclude Many, Study Suggests . The study is not published yet and was presented at a conference in Iceland.

The Times reports:

The study results, presented on Thursday at a meeting of the Icelandic Medical Association, are still preliminary, but they offer the latest and most dramatic estimate of how tightening the criteria for autism could affect the rate of diagnosis. Rates of autism and related disorders like Asperger syndrome have taken off since the early 1980s, to prevalence rates as high as one in 100 children in some places. Many researchers suspect that these numbers are inflated because of vagueness in the current criteria.

The conference program doesn’t have abstracts, just paper titles. Prof. Volkmar had two talks on autism: “The Changing Face of Autism: An Introduction and Overview” and “Understanding Autism: Implications for Health Care”. This leaves us with the Times article as our source for information.

According to the Times:

In the new analysis, Dr. Volkmar, along with Brian Reichow and James McPartland, both at Yale, used data from a large 1993 study that served as the basis for the current criteria. They focused on 372 children and adults who were among the highest-functioning and found that over all, only 45 percent of them would qualify for the proposed autism spectrum diagnosis now under review. The focus on a high-functioning group may have slightly exaggerated that percentage, the authors acknowledge.

The Times has quotes from Catherine Lord (who, amongst other achievements, is one of the authors of the ADOS ) who disagrees with Prof. Volkmar to some degree:

Dr. Lord said that the study numbers are probably exaggerated because the research team relied on old data, collected by doctors who were not aware of what kinds of behaviors the proposed definition requires. “It’s not that the behaviors didn’t exist, but that they weren’t even asking about them — they wouldn’t show up at all in the data,” Dr. Lord said.

The question of how the DSM 5 will change the criteria for how autism is defined has been a subject of great speculation and some study. One can find parents claiming that the DSM 5 is designed to redefine autism as only “high functioning” all the way to autistics worried that many with Asperger syndrome will no longer be classified as autistic.

The results presented by Prof. Volkmar would suggest that “classic” autism, PDD-NOS and Asperger syndrome would all see significant changes:

The likelihood of being left out under the new definition depended on the original diagnosis: About a quarter of those identified with classic autism in 1993 would not be so identified under the proposed criteria; about three quarters of those with Asperger’s would not qualify; and 85 percent of those with P.D.D.-N.O.S. would not.

As noted above, this is not the first study to consider the DSM 5 and autism. For example, a group from Finland published Autism spectrum disorders according to DSM-IV-TR and comparison with DSM-5 draft criteria: an epidemiological study . they found the DSM-5 draft criteria were ” less sensitive in regard to identification of subjects with ASDs, particularly those with Asperger’s syndrome and some high-functioning subjects with autism.”

Abstract
OBJECTIVE:

The latest definitions of autism spectrum disorders (ASDs) were specified in DSM-IV-TR in 2000. DSM-5 criteria are planned for 2013. Here, we estimated the prevalence of ASDs and autism according to DSM-IV-TR, clarified confusion concerning diagnostic criteria, and evaluated DSM-5 draft criteria for ASD posted by the American Psychiatry Association (APA) in February 2010.
METHOD:

This was an epidemiological study of 5,484 eight-year-old children in Finland, 4,422 (81%) of them rated via the Autism Spectrum Screening Questionnaire by parents and/or teachers, and 110 examined by using a structured interview, semi-structured observation, IQ measurement, school-day observation, and patient records. Diagnoses were assigned according to DSM-IV-TR criteria and DSM-5 draft criteria in children with a full-scale IQ (FSIQ) ?50. Patient records were evaluated in children with an FSIQ <50 to discover diagnoses of ASDs.
RESULTS:

The prevalence of ASDs was 8.4 in 1,000 and that of autism 4.1 in 1,000 according to DSM-IV-TR. Of the subjects with ASDs and autism, 65% and 61% were high-functioning (FSIQ ?70), respectively. The prevalence of pervasive developmental disorder not otherwise specified was not estimated because of inconsistency in DSM-IV-TR criteria. DSM-5 draft criteria were shown to be less sensitive in regard to identification of subjects with ASDs, particularly those with Asperger’s syndrome and some high-functioning subjects with autism.
CONCLUSIONS:

DSM-IV-TR helps with the definition of ASDs only up to a point. We suggest modifications to five details of DSM-5 draft criteria posted by the APA in February 2010. Completing revision of DSM criteria for ASDs is a challenging task.

  1. RAJ:
    Fred Volkmar led the DSM-IV task force that conducted the autism field trials for DSM-IV. Allen Francis was the editor of DSM-IV and has now distanced himself from what should have been the crowning achievement of his career in psychiatry, being selected as the editor for DSM-IV (1994). He has publicly stated that the field trials of DSM-IV failed to predict the false epidemics of autism, attentional disorders and bi-polar disorder. DSM5 is a response to the overdiagnosis of autism. Beginnning in with the introduction of DSM-III (1980)the criteria for autism diagnosis has been expanding with each sucessive edition of the DSM. http://www.unstrange.com/dsm1.html This is a natural response where the pendulum has swung too far and which is now heading back towards more restrictive diagnostic criteria. All it demonstrates is that no one can define autism based on behavior and if you can't define a problem you can't solve it.
  2. Sullivan:
    "the crowning achievement of his career in psychiatry" That would be rather sad, actually. An administrative post like that. An important one, but a researcher would want to make a mark in original work typically. (note--Frances with an "e") "All it demonstrates is that no one can define autism based on behavior" What a strange comment. Autism is and has been defined based on behavior. The existence proof is right there that your statement is incorrect. Do you mean that it isn't a precise way of classifying a single entity, much less a plural entity as autism undoubtedly is? I'm sure those in the field would love a better method. It isn't like they know a better way and are hiding it for some arcane purposes. The same goes for those working in the field in a great number of entries in the DSM. Got any other obvious observations to make?
  3. livsparents:
    Are you getting the feeling that Volkmar is shaking the proverbial hornets nest, to stir up opposition to the DSM5 or at least some careful scrutiny of it? I don't know how well publicized it was, but I found the following on the DSM5 homepage...there is one more public commentary opportunity on the DSM5 coming up in the Spring of 2012: "The 2nd commenting period was not the final opportunity for you to submit feedback. In spring 2012, we will open the site for a third and final round of comments from visitors, which will again be systematically reviewed by each of the work groups for consideration of additional changes." Look for some follow up by Volkmar sometime early spring...to coincide with the DSM5 public commentary date and/or autism awareness month in April...just a hunch
  4. Chris:
    I don't know. My son has never been diagnosed with autism. When he was three years old the neurologist assured me that he was not autistic, but that was in 1991. With the new rules, I doubt he would qualify. But then again, his IEPs were all based in his needs, not a diagnosis. When he was a senior in high school the school psychologist noted that he would have had an autism diagnosis under the DSM-IV criteria, and mentioned he has several autistic characteristics (including stimming). Then she added that he would then have been in the school's autistic program, and the result would be that he would have actually lost services. I have noticed over the years that some of his special preschool classmates have been diagnosed with autism as older children. Some were more functioning than my son, others not so much (one is still has severe neurological issues, but is a very sweet young man). Plus some of his classmates were dropped from all special ed. criteria prior to middle or high school (okay, the one kid with the hearing loss is still hearing impaired). This is why I am ambivalent about the DSM rules on autism. It is based on behavior, speech, language, etc. It is not something that is truly quantifiable like mobility, or my son's friend who had to wear hearing aids. And since that young man's hearing aids worked well enough he asked that he be removed into the high school's deaf and hard of hearing program.

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