A Matter of Debate: Are the Proposed Changes in Diagnostic Criteria for Autism Too Restrictive?
A proposed revision to the Diagnostic and Statistical Manual of Mental Disorders (DSM) — including some potentially major changes in the classification of autism spectrum disorders — is the cause for debate among neurologists and psychiatrists who diagnose and treat neurodevelopmental disorders, as well as the patients and families who would be directly affected. Parents and patient advocates are concerned that some autistic children may lose out on specialized school services under the new criteria.
The DSM revision, the first in 17 years by the American Psychiatric Association, would create a single diagnosis of autism spectrum disorder, eliminating the sub-classifications of Asperger syndrome and pervasive developmental disorder-not otherwise specified (PDD-NOS). In order to qualify for an autism spectrum disorder, individuals will be assessed in just two categories: social communication/interaction and restricted/repetitive behavior. (The DSM-IV treated social communication and interaction as two separate categories, allowing for more flexibility in diagnosis.)
Some experts claim that the very broad DSM-IV criteria have allowed for over-diagnosis or misdiagnosis of individuals without autism or with other disorders. There has been a notable climb in the number of children diagnosed with autism in recent decades, with estimates numbering as high as one in 100 children. But in interviews with Neurology Today, some autism experts say the proposed new criteria may be too stringent, running the risk of excluding higher-functioning individuals.
WHY CHANGE THE CRITERIA?
“I think that there's a general desire to make the criteria more specific, less broad,” said Thomas W. Frazier, PhD, of the Cleveland Clinic Children's Hospital Center for Autism and Center for Pediatric Behavioral Health. Clinicians felt that some individuals might meet DSM-IV criteria but did not necessarily have the syndrome of autism, he added.
Fred R. Volkmar, MD, Irving B. Harris Professor in the Child Study Center and Professor of Pediatrics, of Psychiatry and of Psychology and chief of child psychiatry at Yale-New Haven Children's Hospital, is not convinced that a change in the criteria was justified. Dr. Volkmar was formerly a member of the DSM-5 Committee, but resigned.
“I would be inclined to be conservative about changes — and I think that's a rule for nomenclatures in general — if you start mucking about with things too much, understanding research becomes complicated because you're looking at different populations,” he said. “The other question is: is it going to affect or impact people's eligibility for service? On both scores I would say that you have to be very careful.”
Dr. Volkmar is working on a study that looks at the impact of the proposed DSM-5 criteria on individuals previously classified as autistic, and seeing more extreme numbers. He presented a slide with preliminary findings at a meeting at the Icelandic Medical Association in January. This reanalysis of data from the DSM-IV field trial looked at the most cognitively able individuals (with IQs of 70 or more) and found that of those in this IQ group previously diagnosed with autism or a related disorder only about 45 percent would qualify for the new autism spectrum diagnosis. The slide also stated that the new approach makes for a major change in the number of ways an individual can qualify for a diagnosis — going from over 2000 potential combinations of criteria to just six.
Because autism is a disorder that often passes through many different “hands” — neurologists, psychiatrists, psychologists, school counselors, etc.— it is very important to have a uniform system of diagnosis that is specific, said Max Wiznitzer, MD, associate professor of pediatrics and neurology at Case Western Reserve University. In my mind, he continued, “the DSM-IV has fragmented the criteria reflecting the social impairment between the socialization and communication categories and, to some degree, making it an artificial split between qualitative impairment in socialization and qualitative impairment in communication.” (For more information, see the sidebar, “Differences Between DSM-5 and DSM-IV Autism Criteria.”)
What the DSM-5 is doing is it's getting rid of subgroups, Dr. Wiznitzer said. “It is saying that we know there are differences, but where individuals draw the line between the subgroups — that causes confusion. If you look at the true communication deficit in autism, it's not whether they speak or don't speak; it's how they use their communicative ability. Usually kids with ASD can use their language to get their needs met but their major area of impairment is in social communication.”
A 2009 study in the journal Pediatrics, which used the 2007 National Survey of Children's Health, estimated the prevalence of ASD in the US at 110 per 10,000. Dr. Wiznitzer said this study had one very surprising finding: Nearly 40-percent of those ever diagnosed with ASD did not currently have the condition. This speaks to the potential overdiagnosis of the disorder, he said. “I sit on a national committee, and when we meet, I ask the group the same question. Who in this room thinks that autism spectrum disorders are being overdiagnosed? And everybody raises their hands.”
As for the more restrictive algorithm, Dr. Wiznitzer was not fazed. I have heard this argument, he said, “that the fact that they've lessened the number of choices you have on the list is going to impair or impede your ability to diagnose someone. My view is that ASD is like being pregnant — you either are or you aren't!”
Concerns about eligibility for services under the new restrictive criteria are valid, according to Dr. Frazier. “If you have folks who no longer meet diagnostic criteria, then the question becomes would they meet the criteria for something else? And would that something else be sufficient enough for them to get the services that they need? If you have somebody with Asperger's, for example, who needs a particular IEP (individualized education plan) to make sure that their educational needs are being met, or that they qualify for outpatient psychology services to help them with social thinking and social functioning, and if they don't meet criteria, then they might lose out on those services.” This question, he said, is what motivated his analysis of the DSM-5 criteria.
If we don't call it Asperger's syndrome anymore, but we still call it an autism spectrum disorder, the individuals still qualify for state services, Dr. Wiznitzer said. We have to ask the question as to why experts and individuals feel the need for a distinct separate label that is not clearly differentiated by neurobiological and neuropsychological studies from high-functioning autism.
Dr. Frazier added that he hopes the DSM-5 Committee would take some of the research into account and that “they seem to be trying to do a reasonable job in making sure that folks with autism spectrum disorders are not lost from the diagnostic criteria.”
No final decisions have been made yet, and the committee still has time to review the data and varying expert opinions. In the spring of 2012, the proposed criteria will be posted on the DSM website and opened up for commentary for two months. After the review period and revision, the official criteria will be released at the American Psychiatric Association annual meeting in San Francisco in May 2013.
More on the debate: Dr. Thomas W. Frazier talks to Neurology Today about why he thinks the change in diagnostic criteria is justified, and how to make it more inclusive for all autism spectrum disorders. Tune in at http://bit.ly/wMHoDR.