Autism

So the book I'm reading right now, JPod, has a character in it who is convinced that everyone around her has a mild form of autism. She works at a videogame development place, so certainly there are some odd people, but it's got me thinking about that diagnosis. As some people know, I am not a believer in most "syndromes" (ADD, ADHD and others I won't name so I don't blatantly offend anyone). They are not helpful in any practical way and often encourage "solutions" that detract from the real (psychological, social and environmental) problems at hand.

However, autism is definitely real (although I it's not really a "syndrome") and people definitely have it in different degrees. But what in the world does that mean? And can I ask a question that could come off as incredibly insulting and ignorant, but which I have no answer for: is autism what used to just be called "mentally retarded"? Because then, of course, I would have to say that all people are autistic in some degree, just as they are all mentally retarded in degrees ranging from nondetectable to debilitating.

When does it start becoming helpful to refer to someone as autistic? How autistic do they have to be in order to get this diagnosis? For instance, if disliking loud voices and being touched by strangers are symptoms, I share them with an autistic person. This is helpful in an I-can-empathize-with-you way, but mild autism would not be a helpful diagnosis for me. It doesn't do anything for me and could only serve to have negative effects (such as feeling helpless to change myself in spite of the condition or lowering my self-esteem or giving me an excuse for bad behaviors). And for a highly functioning autistic, why would the diagnosis be helpful when in theory they could already be counteracting the condition by behavioral therapies not directly related to autism? Is autism only a helpful diagnosis for those it effects most severely and can't comprehend what it means, and if so, how is it helpful to be diagnosed in this way?

Anyway, random thought for the day.