Autism and diagnostic substitution

11 Apr

As we all know, one of the planks underpinning the platform of the vaccine/autism hypotheses is the idea of an autism epidemic. This ‘supporting idea’ says that there was a sudden, massive increase in the amount of people with autism. This is as opposed to a sudden massive increase in the amount of people _diagnosed_ as autistic, or even more accurately, a sudden, massive increase in the amount of people _eligible_ to be diagnosed.

This was all in and around 1992 when two things happened. The first thing is that the vaccine schedule was altered. The second thing is that the DSM was altered, widening the criteria and allowing in many more people to collect an autism diagnosis then pre-1992.

The first idea – that there was a de facto increase in the amount of people with autism – is the one favoured by those who think autism is caused by/triggered by vaccines. Personally, I feel that numbers two and three have more validity. But the anti-vaccine people need to have an epidemic in order for the vaccine hypotheses to hold water. No epidemic = no sharp rise = no need for an obscure hypothesis to account for it.

However, as Professor Grinker points out in Unstrange Minds:

Doctors now have a more heightened awareness of autism and are diagnosing it with more frequency, and public schools….which first started using the category of autism during the 1991 – 1992 school year are reporting it more often….Epidemiologists are also counting it better.

Unstrange Minds, Page 4

Five big pieces of the awareness puzzle started to come into play. Another one (and yes, I’m stretching this a bit) is what’s called the ‘Rainman‘ phenomenon. This refers to the first real emergence of autism in popular media which purportedly led to many more people becoming aware of autism within their own communities.

As part of Unstrange Minds, Grinker went to Korea and looked at the autism experience there. This is part of what he found:

When [Milal School] was being built in the mid-1990s, some of the wealthy residents of this quiet neighborhood south of the Kangnam River in Seoul picketed the site, cut the school’s phone lines, physically assaulted school administrators, and filed a lawsuit to halt construction, because they believed that the presence in the neighborhood of children with disabilities would lower property values. The school opened in 1997, but only with a compromise. It was required to alter its architecture so that the children were completely hidden from public view. Some of the protestors were brutally honest. They said they didn’t want their children to see or meet a child with autism.

Its my opinion that this sort of thing was not too uncommon in the not-too-distant-past of the West. I know from my own experience that offering services for some forms of mental illness are protested against by residents close to the proposed services in the UK. People fear what they don’t understand.

In the case of autism, I think we in the West are past Korea’s point. We are very much more accepting of autism as an existing state and thus people are more prepared to see it and more people _do_ see it. Would you have wanted to take your autistic child out for a walk to the shops if you lived in Korea in the mid-90s? No, me neither. In this country in 2008 I do so with no worries at all.

But believing these things are accurate and having evidence to support that belief are two different things.

Professor Dorothy Bishop of Oxford University led a team to study:

whether some children who previously had other diagnoses are now being diagnosed with autism. We applied contemporary autism diagnostic criteria to adults with a history of developmental language disorder, to discover whether diagnostic substitution has taken place.

The results were eyebrow-raising. In total, 12 (31%) of the participants would’ve been diagnosed as being on the spectrum, of which 8 (21%) would have been diagnosed with ‘classic’ autism.

Bishop et al are quick to point out that:

….it would be rash to conclude that increasing prevalence of autism is entirely explicable in terms of broadening diagnostic criteria

which is very true but it also an inescapable conclusion that, in the words of some of the anti-vaccine believers, these kids were ‘missed’. Or as Bishop et al put it:

….this study provides direct evidence of diagnostic substitution, indicating that many children who were diagnosed with severe language disorders in the 1980s and 1990s displayed behaviours that would be regarded as meriting a diagnosis of ASD according to contemporary criteria. This appears to be a direct result of changing diagnostic criteria from DSM-III through DSM-IIIR and DSM-IV.

One aspect of the study has already caused it to be ignored by the anti-vaccine believers. The fact that Professor Bishop is a Wellcome Research Fellow. I wanted to talk to her about this and find out what that meant. She replied that:

The Wellcome Trust is not involved with manufacture of pharmaceuticals – that’s a common misperception….

And she attached a brief commentary on the subject that is produced by the Trust.

We do not make pharmaceuticals.

The Wellcome Trust is frequently and erroneously thought to be a drugs company, or to have been the charitable arm of a drugs company.

The confusion stems from the fact that from 1936 the label ‘Wellcome’ was shared by two entities, both founded by the same man:

1) the Wellcome pharmaceutical company (confusingly known as the Wellcome Foundation Limited in the UK)
2) the Wellcome Trust.

The Wellcome Trust (the charity) was established by the will of Henry Wellcome to be the sole shareholder of the pharmaceutical company, and to use the profits for charitable aims. Until 1986, the Wellcome Trust was the sole owner of the pharmaceutical company, which generated all of the charity’s income.

In 1986, the first of two share sales created a public limited company, Wellcome plc, which owned the Wellcome pharmaceutical company. The second sale took place in 1992, reducing the Wellcome Trust’s shareholding to around 25 per cent of Wellcome plc. Further asset diversification resulted from the 1995 merger of Wellcome plc with Glaxo plc, creating Glaxo Wellcome plc, which subsequently merged with SmithKline Beecham plc to create GlaxoSmithKline plc.

The Wellcome Trust maintains a small stake in GlaxoSmithKline, as part of a broad portfolio of investments that includes equities, property and other forms of corporate investment. It has always made all of its funding decisions completely independently of the pharmaceutical company.

Professor Bishop is the first to point out the limitations of this study – its small sample size. But this is, as she states, direct evidence of diagnostic substitution and, should the percentages be mirrored elsewhere, somewhere between 20% – 30% of the ‘epidemic’ could in fact be attributed to diagnostic substitution.

2 Responses to “Autism and diagnostic substitution”

  1. Joseph April 11, 2008 at 17:31 #

    And let’s not forget there’s a substantial amount of evidence that points in the same general direction.


  1. The Claim of the Autism Epidemic - April 15, 2008

    […] and psychological perspective. In a review of Prof. Bishop’s study, blogger Kev at Left Brain/Right Brain referenced Unstrange Minds: Remapping the World of Autism by anthropologist Roy Richard Grinker. […]

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