Another possible explanation for such a rise that I have seen repeatedly given is that the methods and basis for diagnosis changed in the early 90s. http://www

Another possible explanation for such a rise that I have seen repeatedly given is that the methods and basis for diagnosis changed in the early 90s. http://www.forbes.com/sites/tarahaelle/2015/01/05/majority-of-autism-increase-due-to-diagnostic-changes-finds-new-study/#3461baaa737c http://www.forbes.com/sites/tarahaelle/2015/01/05/majority-o... Its also discussed here on Fresh Air by the author of a book on Autism called Neurotribes. " But because no one really explained to parents exactly what had happened - that the diagnosis had been completely rewritten - that, you know, autism by the end of the 1980s and the early 1990s was not your grandfather's autism, you could say. It was much more broadly defined because no one ever explained to the lay public what had happened with the diagnosis. When the numbers started going up, parents very understandably became very alarmed. And the media was sort of blindsided by the sudden spike in diagnoses." http://www.npr.org/2016/09/09/493148713/neurotribes-examines-the-history-and-myths-of-the-autism-spectrum http://www.npr.org/2016/09/09/493148713/neurotribes-examines...