I think that study goes up to 2005. When they invented the spectrum in the DSM-5 is when they really went balls to the wall on diagnosing. It’s like 1 in 30 kids now and as high as 1 in 12 boys in California as of 2024. A comparison of DSM-4 prevalence of ‘classic’ autism and level-3 (most support required) DSM-5 autism spectrum disorder might provide more information. As it stands down they are comparing rates of DSM-3 and DSM-4 classic autism with DSM-5 autism spectrum disorder levels 1-3.
I have studied this extensively because a family member was diagnosed and a number of people in my family have Asperger’s like symptoms including myself. I share the same polymorphism on a gene with said diagnosed family member (who is high functioning but has severe ADHD).
The problem is Asperger’s does not fit into the classical head banging, self-mutilating destructive nature of full blown autism. The EEG is different also, so I was told by a a neurologist (family member is Aspie according to the old criteria).
A few years ago they had several different categories that were not autism such as pervasive developmental disorder and Asperger’s. There were similarities among the different types but they were clearly different disorders.
IMHO the problem is lumping them all under autism spectrum disorder makes it LESS likely to find cures or proper ABA therapies for these individuals.
It’s as if we decided to come up with a “cranial pain disorder” for any headache and treated every headache as if it were a migraine. That makes no sense either.
My observation does not negate the fact that chronic disorders, be they autism, Asperger’s or ADHD for that matter have seen dramatic increases since the 1990s (I don’t have ADHD, my younger family member does).