Saturday, August 02, 2008

Autism is Rising! Autism is Rising!

TV might cause autism. - By Gregg Easterbrook - Slate Magazine

    Clearly this study did not get much traction as I have heard nothing more about it in the nearly two years since it was released. However, it is still a nice starting point for a subject I have been thinking about for a while. The author, and the authors of the study, try to link an increase in the incidence of Autism with the increase in children's programing (and the following increase in television consumption by toddlers) in the early 1980's. It is, I admit, an interesting hypothesis. There is only one small problem. Before you prove a cause for the increase in the incidence of Autism shouldn't you first prove that Autism is on the increase?

    The study in question claims that the incidence of Autism has been increasing since 1980 and they look for a cause from external factors to explain the increase. In the article, however, there is no mention at all about changes in the definition, and diagnoses of Autism over the same period. Prior to 1980 only the most severe cases were diagnosed as Autism. Since 1980 the diagnosis of Autism has been expanded to a "spectrum" that runs from very mild to severe. While the article mentions that Autism diagnoses began increasing in 1980 they do not report the the DSM-III was published in 1980 with an expanded definition of Autism followed by a revision of the DSM-III in 1987 which further expanded the definition. The article also fails to mention that the "incidence" of Autism really began to skyrocket in the mid 1990s. Is it a mere coincidence that the DSM-IV was published in 1994 with yet another expansion in the definition of Autism?

    My youngest son, Jacob, was diagnosed with Autism Spectrum Disorder in 2003 when he was five years old. He is on the mild end of the spectrum and I am very certain he would not have been diagnosed as Autistic ten years earlier let alone twenty or 25 years earlier. I remain open to the possibility that the actual prevalence of Autism is increasing. However, at this time I have seen no evidence that proves the increased incidence is due to anything more than changes in "diagnostic practices, referral patterns, availability of services, age at diagnosis, and public awareness."

    I hope you will keep this in mind the next time you read an article or hear someone sounding the alarm of the increase of Autism. And the next time someone refers to the Autism epidemic ask them if it is worse than the schizophrenia "epidemic". The incidence of schizophrenia is about 10 per 1000 compared to Autism Spectrum Disorder which is around 6 per 1000. Perspective matters.

    For further reading Wikipedia has a couple of well written articles here and here.

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