In autism- if the increase is from diagnosis, should adult diagnosis be through the roof?

Maybe not: It may be that some children outgrow what is now being diagnosed as autism (& this may explain some of the "success" of costly interventions). It may be that kids who are otherwise developmentally disabled get the autism diagnosis for the increased $$ benefits it may offer. I've suggested autism twice at autopsy from the cerebellar changes & both times families agreed it fit. Still a mystery!

Different era : Those who showed signs of autism many years ago were tossed into classes for the mentally retarded and or special schools without specific labels.As adults they functioned at whatever level possible, often kept at home or at state schools. Its hard to tell a tiger from other cats until you know the difference.