Saturday, May 31, 2008

A Tale of Two Epidemics

If you were a Martian who had just landed on Earth, somewhere in the United States, and you opened a newspaper or got on a mainstream news website, you would get the impression that two things were happening to the human race:
  1. Our children were all being stricken with a mysterious and terrible disease called "autism," which eradicates the personality and prevents the child from ever having any sort of life of his or her own, and

  2. Large numbers of us were suddenly blowing up like balloons, growing larger and larger with no sign of stopping, and falling prey in record numbers (and at ever-decreasing ages) to such maladies as hypertension, Type II diabetes, heart disease and atherosclerosis.

In case the sarcasm doesn't come across, I don't believe either of those things are happening. I believe humanity looks much as it always has, with a wide range of mental and physical types.
I also believe that those types are determined largely by genetics, which would make it difficult to have an "epidemic" of obesity or autism --- you might as well entertain the idea of a tallness epidemic.

"Now, wait a minute, Lindsay," I hear you saying. "You can't be telling us you don't believe the way we're living as a culture has no effect on our health! In fact, we're pretty sure we've caught you implying the opposite on multiple occasions! What's up with that?"

You're right. I do believe a person's lifestyle has an effect on their health, their body composition and where their weight falls within a genetically determined set-point range. I'm as ready as any crusading zealot to condemn our culture's habits of driving everywhere, working long hours at sedentary jobs, goofing off by sitting in front of the TV or computer instead of playing in the yard, and eating greasy, calorie-dense but nutrient-poor fast food. I'm not willing to extend this condemnation into a personal condemnation of every person whose body does not pass aesthetic muster with me, however. Doing that assumes that poor health habits inevitably lead to fatness, and that fatness is a reliable marker of poor health habits, both of which are just not true.

What does any of this have to do with autism? Well, as I've said previously, I think our culture fixates on a One Right Way to Be, whether it's physical, intellectual or spiritual. Like the ancient Greeks, we lazily equate (what we perceive as) physical beauty with health and goodness. Since the current ideal of beauty is ridiculously thin, is it any wonder people criticize themselves and their neighbors for being morbidly obese? By comparison with the ideal, we are. But because few people are willing to disregard the ideal, we end up thinking it's our bodies that are falling short. Similarly, since psychiatry has long focused on the many forms of mental dysfunction, we have come to think of mental health as the narrow strip of territory not claimed by any of the lurking horde of psychoses and neuroses.

There is also a common motif in the history of diagnosis of autism and obesity that contributes to the widespread belief that the prevalence of both conditions is rising rapidly: they both underwent a revision in the diagnostic criteria within the past decade or so that made them both much more common. With the switch to the DSM-IV, more subtypes of autism were made available (and, obviously, when there are more categories, more people find one that fits them!), and Autistic Disorder itself became a more flexible diagnosis (of sixteen suggested traits, you only had to meet six to qualify). Likewise, in the late 1980s the cutoff point for the "overweight" category of Body Mass Index moved from 27.3 (women)/27.8 (men) to 25, shunting millions of Americans into the overweight category overnight. Did those people get any fatter, or less healthy? No. Think about that the next time you hear the statistic that two-thirds of American adults are overweight or obese.

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