The CDC has been rapidly increasing its estimate of children with autism for years. It's tripled in the past 15 years.

This has lead to a lot of speculation, including dramatic claims like vaccines causing autism.

My physiology-major wife tells me that the enormous increase is likely simply increased awareness and alterations to its definition.

But I never hear anything definitive. Even with changes to awareness, definition, etc., given that autism is a common, incurable, lifelong condition, isn't this is really easy to answer?

  1. Take a population sample.
  2. Test for autism using chosen, fixed criteria.
  3. Analyze how age correlates to the measured autism rate.

Okay, maybe not "really easy", but as easy as other physiological population studies.

Has anyone done this and found the answer? Is actual autism prevalence increasing?

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    $\begingroup$ Welcome to Psychology.SE. I think that any definitive answer to this question would be very much based on opinion rather than hard facts. As you said your wife pointed out, increases within statistical data can be for many different reasons including increased reporting, better records, increased awareness (inside and outside mental health fields)... The same can be found with national crime statistics and many other datasets. As for estimates, they are just that... estimates $\endgroup$ – Chris Rogers Dec 30 '18 at 8:45
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    $\begingroup$ Potential duplicate: psychology.stackexchange.com/q/4515/21 $\endgroup$ – Steven Jeuris Dec 30 '18 at 19:38
  • $\begingroup$ @ChrisRogers :/ Sad to hear there haven't been any reputable clinical studies. $\endgroup$ – Paul Draper Dec 31 '18 at 3:38
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    $\begingroup$ Not to fully invalidate your question and suggested method for a study, but for one, I know that it is possible to lose the diagnosis of autism over the years. E.g.: iancommunity.org/ssc/… $\endgroup$ – Steven Jeuris Dec 31 '18 at 10:25
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    $\begingroup$ In some countries it decreased psychology.stackexchange.com/questions/20504/… $\endgroup$ – Fizz Jan 1 '19 at 20:49

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