Is the Autism Epidemic a Myth?

As convincing as Grinker's analysis seems, arguments about the apparent epidemic will probably continue. It's simply impossible to accurately reconstruct the past incidence of the disorder, given how radically definitions have changed. Those who believe the increase is real often focus on the mysterious paucity of autistic adults. With their conspicuous symptoms like hand flapping and little or no language, "I think we would be recognizing them in institutions," says Dr. Robert Hendren, executive director of the M.I.N.D. Institute at the University of California, Davis.

Grinker's answer is that autistic adults are out there but wearing other labels. "Where are all the adults with fetal alcohol syndrome?" he asks. No one over 40 has the condition, thought to affect up to 1 in 500 kids today, because it was not recognized until the mid-'70s. "But no one would say alcoholism among pregnant women just started," says Grinker.

Grinker, whose 15-year-old daughter is autistic, concedes that there's something reassuring about the idea of an epidemic: "Thinking about any disorder as an epidemic is easier than thinking about it in terms of multiple causes, shifting definitions and a scientific reality we are only just beginning to understand." Besides, if a disease suddenly spikes, it seems more plausible that the increase could be reversed--if only we could find the mysterious environmental trigger. With autism, though, that hopeful scenario seems just too simple.