Claim: Autism Prevalence Has Exploded, and We’re Not Just “Noticing It More”

Verdict: Largely false and misleading

“In 1970, the biggest epidemiological study at that time in history was performed [...] they were looking for autism, and they knew what autism looked like. And they came back with an incident rate of 0.8 per 10,000. So less than in 1 in 10,000. The rate, according to CDC today in this country, is one in every 31 children. [...] One of the talking points [...] is, oh, we're just noticing it more. But this is an absurdity.”

Trump signs executive order on childhood vaccines(from 7:10)

– RFK Jr

During the signing of an executive order on vaccines, one point made by both RFK Jr. and Trump about autism prevalence is very common: is there something weird going on with the increasing rate of autism?

What the Study RFK Jr. is Referencing Actually Says

RFK Jr. mentions this study specifically. As he said, it was released in 1970 and involved around 900,000 children in Wisconsin.

The study looked at the DSM-II entry for “childhood schizophrenia,” and notes three groups of cases:

• A) What they call “classic” infant autism. This included an early onset, a desire for “sameness,” withdrawal and speech problems.

• B) These children had some of the classic autism symptoms but the onset was later.

• C) Likely psychosis with some complicating factors making diagnosis difficult.

RFK Jr. slightly misquotes the results for group A. Their prevalence was 0.7 cases per 10,000 children. Including group B would raise this to around 2.4 per 10,000. He also incorrectly implies the authors screened all 8-year olds in the state, but this is incorrect. They found cases from existing records from healthcare facilities for kids aged 3 to 12.

 It is true that a recent CDC estimate puts the figure at 1 in 31, based on modern diagnostic criteria (ICD-9 or 10). The modern DSM edition is V.

What’s Really Happening

You may have noticed that group B above would likely be just considered on the autism spectrum today. The differences between the 1970 diagnostic criteria and modern ones are hard to overstate, now encompassing Asperger’s syndrome, Rett’s disorder and others, and clearly differentiated from schizophrenia.

Despite RFK’s assertion, studies suggest that these changes, increased awareness and more effective screening are responsible for (at least) most of the apparent rise in diagnoses. For instance, previously under-represented groups like women and non-white people have a sharper rise in diagnoses.