Majority Of Autism Increase Due To Diagnostic Changes, Finds New Study

Almost two thirds of the increase in autistic Danish children results from how autism is diagnosed and tracked, found a new study in JAMA Pediatrics, lending more support to the idea that the apparent rise in autism rates, or at least most of it, is unlikely to be “real.” That is, the increase is likely more about previously-unidentified autistic individuals getting an autism diagnosis than more individuals actually developing autism.

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What makes this study strong is its size, with well over a half million children born over a decade, and the use of the national health registry for the data. “The authors have at hand a more exhaustive and thorough database than is available pretty much anywhere else, and their findings are echoed by some other studies,” said Glen Elliott, chief psychiatrist and medical director of Children’s Health Council in Palo Alto, Calif. But it’s less clear, Elliott told me, how much these findings can be generalized to the U.S. Autism prevalence in Denmark, 54 of every 10,000 children, is still far lower than that of the U.S., with 147 of 10,000 children, though the latter, he said, uses a less precise tool* than direct access to patient records, as used in this study.
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The way autism is defined in the U.S. has changed dramatically since 1980, when it first appeared in the DSM-III as “Infantile Autism” and could only be diagnosed in children whose symptoms began before they were three years old. Autism spectrum disorders have expanded to include diagnosis without a specific age requirement beyond the “early developmental period” and without requiring significant language impairment in the recently revised DSM-5.

The vast majority of people diagnosed with autism spectrum disorders today would never have qualified under the 1980 classification, and no formal classification separate from schizophrenia existed before then. So it’s not surprising that numbers have increased in the U.S. The CDC puts the current incidence of autism spectrum disorders at 1 in 68, or about 1.5 percent,* though this figure may also mislead those unfamiliar with the broad diversity – quite literally, the neurodiversity – that autism encompasses since popular images of autism still unfortunately misrepresent the condition. The 1 in 68 refers to individuals all over the autism spectrum, from those who need only some supports and accommodations to those who need very substantial support. It is the latter group, especially those who have little spontaneous language (verbal or nonverbal) who are the stereotypical face of autism, but they are the minority of autistics.


Majority Of Autism Increase Due To Diagnostic Changes, Finds New Study