I don't know how much over-diagnosis happens
AFAIK nobody is collecting statistics-- that's a very hard kind of statistic to collect.
but there does seem to be a considerable number of young children who "outgrow" it
I don't know any such cases personally, and those covered in the literature are comparatively few. All children learn and grow, and many who have challenges as young children grow into adults who have learned to manage their difficulties relatively smoothly (although often with invisible effort).
My take on that question is very like that expressed here:
http://jerobison.blogspot.com/2013/01/can-we-outgrow-autism.htmlwe filled out rating scales plus there were a couple tests looking at affect recognition (reading emotions on people's faces?) and "theory of mind", all of which he did fine on.
Some autistic people have theory of mind; it's a misconception that they can't. My DS can do quite well on those tests. Still autistic.
The ADOS attempts to quantify the social engagement aspect of autism for diagnostic purposes-- it's the best instrument I know of for making the distinction. Rating scales aren't enough IMO.
The reason I recommend going to a major pediatric autism center is that they have access to and much more experience with the latest testing instruments than the average private neuropsych might. And they've seen a lot more kids, so the practitioners tend to have a quite nuanced sense of where the diagnosis applies. Not to say you can't have a bad experience there, just to say that going where the expertise and experience is makes a lot of sense to me.
DeeDee
