Who will go nuts?

Predicting mental illness is usually no better than gambling, but we keep trying.

By Robert Burton, M.D.

Dec 6, 1999 | Maybe it's because we're all on edge, spending time with our families during the holidays. Or maybe it's the approaching millennium, but I've been getting questions like these lately: "My son's acting weird. What are the chances that he's becoming schizophrenic?" "I have a mother who has breast cancer. What's the likelihood that I'll get it?" and "What are the odds that my husband caught herpes from a toilet seat?"

Whether evaluating a patient with a family history of cancer or elevated cholesterol level; or passing judgment on a violent rapist scheduled for possible parole, doctors are being asked to become scientific clairvoyants. Medicine has become the highest-stakes game in town, and we physicians are the de facto oddsmakers.

As a passionate poker player, I am aware of the vagaries of predictions. A few weeks ago, playing Texas Holdem in a local casino, I called a final bet, knowing that there was only one hand I could beat. Fortunately, that's the very hand my opponent had. While I scooped up the chips, everyone laughed. Some murmured reluctant praise, others groused that my call was stupid, an utter fluke. I shrugged in a fabulous display of false modesty. On the way home, my feeling of smugness lapsed into doubt. Had my read of the other player been an informed hunch, a gut feeling, innate talent or pure luck? To really know, I would need to have available for statistical analysis all the prior poker decisions I'd ever made, an impossible task given my gambler's version of a selective memory. Now the smugness was really gone. It was pure folly to think that I could tell the difference between skill and luck based on a single experience.

I went home, counted my winnings and told myself that the cash was empirical evidence. But I knew better.

The morning following the poker game, a journalist friend phoned. She wanted to know if there were psychiatric tests that might detect potentially suicidal pilots. My first response was, "Are you kidding? Human behavior isn't that consistent." She continued, "Certainly there must be some traits that would be sufficiently alarming to ground a pilot before he got into trouble?"

"Wishful thinking," I said, before agreeing to do some homework.

Medicine has the same problem with predictions as my poker playing. We mentally tabulate our past experience and, from this inaccurate, selective database, make all sorts of serious, life-and-death decisions. Sometimes the predictions pan out. Sometimes they don't, particularly in the vaguest of all specialties, psychiatry. So, what is known about psychiatric predictions?

(A brief caveat -- I have several psychiatrist friends whom I respect. The following is not meant as a blanket condemnation. Besides, they can easily retaliate by asking how much good a neurologist does, a point with which I would readily agree.)

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