I was a little skeptical all along of the new wave of autism diagnoses the past decade or so (though my skepticism did nothing to sway my absolute empathy for parents and children of those who suffer from the disease, I just had a hunch something else was up), it seems that the Economist has unveiled a different reason for this:

FASHION is a strange thing, and many fields are susceptible to it—not least, medicine. There has, for example, been a vogue (among commentators, if not among doctors) to ascribe the rising number of cases of autism diagnosed over the past couple of decades to childhood vaccinations against measles, mumps and rubella. That this is fashion rather than reality is suggested by the fact that the explanation proffered in Britain has been that such vaccines provoke an immune response that damages the nervous system, whereas Americans have blamed residual mercury in the same vaccines.

It is now pretty well established that vaccination does not create autism. But the rise in the number of recorded cases is real enough. In Britain, for example, the rate of diagnosis has risen from 50 per 100,000 in 1990 to 400 per 100,000 today. That must have a cause. And one popular hypothesis is that this cause, too, is fashion—but among doctors rather than columnists.