there are definitely many levels to the autism spectrum -- and some research i've done recently shows there are a lot of adults with undiagnosed autism - tending more towards Asperger's -- and at least a few of them are probably certified divers as well. I wonder how many of them are solo divers? something to ponder.
My son is a certified diver and just recently diagnosed with ASD (Asperger's) as a young adult. He is a natural diver (but still very inexperienced) and sometimes I worry that he is too comfortable underwater.