[Smokin' Joe]

You have to consider that 'autism' has been redefined and broadened as a diagnosis. It may be that no larger a proportion of the population has it, just that the definition has changed.

That does not eliminate other possible factors and would be a study in itself, rendered more difficult by the redefined diagnostic parameters.

[Hugin]

Good point. In the old days they would have said “he’s touched” and that would be that. Just like a wide range of diseases were lumped under “natural causes” and “old age”.