Maybe autism has increased, maybe not. Certainly the term was not used previously. However the funding available for autism-related research has boomed dramatically in the last 20 years. The availability of funds for researchers has a dramatic effect on the tenor and number of grants, as well as discourse in the scientific and lay literature.
Take that to the bank.
Longing back for the good old days when the trendy fad was for ADHD research, grants, special classes for the much diagnosed and even more drugged to the eyeball young'uns walking around like zombies whacked out on Ritalin. Must have new drugs, trendy names to deal with the new malady's.