There has been an "epidemic" of autism in the last fifteen years. This used to be a very rare condition diagnosed less than once in every two thousand kids. Now it is diagnosed once in a hundred. We will elsewhere take up the foolish theory that this was cause by vaccination. Here we will trace the real causes.
People change slowly, if at all. In contrast, fads in psychiatric diagnosis can come and go in a fast and furious fashion. The autism fad resulted from changes in DSM4 (published in 1994) interacting with a strong societal push.
There were two DSM4 contributions:1) the inclusion of a surprisingly popular new diagnosis, Asperger's Disorder; and, 2) much less importantly, editorial revisions meant only to clarify the criteria for Autistic Disorder, but which may have inadvertently lowered the threshold for its diagnosis.
The societal contributions were: 1) expanded school and therapeutic services whose reimbursement often required an autism diagnosis; 2)increased advocacy; 3)reduced stigma- especially when many successful people admitted to having Asperger's;4)extensive press coverage;5)an explosive growth in internet information and social interaction; and as a result of all these,6)improved surveillance and identification by doctors, teachers, families, and by the patients themselves.
For many of the newly identified patients, getting a diagnosis has brought the advantages of:1)improved school and therapeutic services; 2) reduced stigma; 3) increased family understanding; 4) reduced sense of isolation and; 5) internet support and camaraderie.
But there are always costs. With its lowered diagnostic thresholds and resulting increased inclusivity, Asperger's brought autism to the fuzzy boundary with normal eccentricity and social awkwardness. Some people are misidentied as having the diagnosis, when they really don't. This is especially true when the diagnosis is made in less expert hands in primary care medical facilities and in school systems.
Overdiagnosis creates the personal costs of: 1) stigma; 2)reduced self and family expectations, and;3) having to undergo unnecessary treament and educational interventions. The societal costs of overdiagnosis are:1) the diversion of scarce educational and therapeutic resources away from those who most need them; and 2) the parental panic and confusion occasioned by the false "epidemic".
The diagnosis of Asperger's Disorder was introduced by DSM4 because its advantages were judged to outweigh its risks. It seemed important to have a specific category to cover the substantial group of patients who failed to meet the stringent criteria for autistic disorder, but nonetheless had substantial distress or impairment from their stereotyped interests, eccentric behaviors, and interpersonal problems.
The public panic about the seeming spread of autism resulted from a misunderstanding of how psychiatric diagnosis works- ie how arbitrary it can be and how sensitive prevalence rates are to changes in definition. As Chair of the DSM4 Task Force, I am partly to blame for not having anticipated this risk. We should have proactively taken steps to educate the public. It would have been useful in advance to predict the changes in diagnostic rates and to explain their causes. We were aware that Asberger's would have a much higher prevalence than classic autism, but we greatly underestimated the magnitude of the difference and the rapidity and degree of the public's panicked sense that the world had changed- rather than just the labels. We failed in our responsibility to make clear to the public and to the press what the labels meant and what they do not mean.
. A new revision of the diagnostic manual is now in its first draft and can be viewed at www.dsm5.org. DSM5 proposes another radical reorganization in how autism is defined. Instead of separating classic autism from Asberger's, there would be one unified "autism spectrum" disorder with a single criteria set. The rationale is that there is no clear boundary between the two and that autism is more conveniently seen as one disorder, presenting with different levels of severity. The DSM5 proposal also has the virtue of attempting to raise the diagnostic requirements for the milder presentations of autism above those required for Asberger's in DSM4. The Work Group is appropriately worried about false positives and the proposed criteria set would theoretically reduce the rate of misidentified autism.
There are two perhaps equally strong arguments against this possibly useful DSM5 proposal: 1)that it will increase the stigma attached to the milder forms of (Asperger's) autistic behavior if they are lumped together with the much more severe, and; 2) because clinicians often ignore the fine points of what is required by the criteria thresholds, the "autism spectrum" may in practice actually expand even further to capture ever milder forms of eccentricity contributing to an even higher prevalence of misidentified "autism". this is obviously the opposite of what the Work Group intends, but it could be an unanticipated and unintended consequence.
The reply to these objections would be that: 1) autism will lose some of its stigma if the public comes to associate it with milder cases; and 2) the Work Group can only do what the science says and can't be expected to predict or prevent misuse once their work is in the public domain.
The first point can be argued either way, but I would strongly disagree with the second. Our DSM4 experience makes clear that the Work Group must consider all the possible risks once the changes are applied (or possibly misapplied) in general medical and educational practice. Ideas generated in rarefied research environments often take on an unfortunate life of their own in the real world.
The DSM5 proposal is highly controversial both within the professional community and among the advocacy groups- with strong supporters and equally strong critics and probably about an equal weight of argument on both sides. When it comes to labelling, the heat of the argument is often a direct reflection that there are no clear right answers. The major point is to ensure that DSM5 not provoke a further misleading "epidemic" of autism. The criteria set should retain and enhance items that will reduce the risk of false positive diagnosis. Proposed changes and alternative wordings need careful field testing in nonspecialist settings to determine their likely future impact on rates. Even small wording changes can have a profound impact on who is, and who is not, diagnosed.
Ultimately, there will not ever be a clear right verdict on the DSM5 proposal to unify autistic disorders within one rubric. The scientific evidence is not overwhelming either way and is subject to different plausible interpretations. The stigma question cuts both ways. The services issues will have to be dealt with whether there is one diagnosis or two.
As I see it, there are four real issues that cut below the controversies:1) The importance of reducing false positive diagnosis by refining the criteria sets and raising the threshold requirements. At a minimum, the goal should be a diagnosis that has considerable stability over time and reduced wriggle room for careless use in general medical and educational settings; 2)the need to educate doctors, psychologists,educators, families, and patients that not all eccentricity is mental disorder; 3)the need to educate the public and the press that diagnostic habits and systems change far faster than people do; and, 4) getting past the ridulous idea that this has anything to do with vaccination.
The way to avoid definitional "epidemics" is to be cautious in changing definitions. The way to avoid panics about them is to be mindful that labels can be misunderstood and can be misleading.