The Nocebo Effect: Placebo’s Evil Twin

The Washington Post has an interesting article about the nocebo effect:

Ten years ago, researchers stumbled onto a striking finding: Women who believed that they were prone to heart disease were nearly four times as likely to die as women with similar risk factors who didn’t hold such fatalistic views.

The higher risk of death, in other words, had nothing to with the usual heart disease culprits — age, blood pressure, cholesterol, weight. Instead, it tracked closely with belief. Think sick, be sick.
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That study is a classic in the annals of research on the “nocebo” phenomenon, the evil twin of the placebo effect. While the placebo effect refers to health benefits produced by a treatment that should have no effect, patients experiencing the nocebo effect experience the opposite. They presume the worst, health-wise, and that’s just what they get.

Another example:

Fifteen years ago, researchers at three medical centers undertook a study of aspirin and another blood thinner in heart patients and came up with an unexpected result that said little about the heart and much about the brain. At two locations, patients were warned of possible gastrointestinal problems, one of the most common side effects of repeated use of aspirin. At the other location, patients received no such caution.

When researchers reviewed the data, they found a striking result: Those warned about the gastrointestinal problems were almost three times as likely to have the side effect. Though the evidence of actual stomach damage such as ulcers was the same for all three groups, those with the most information about the prospect of minor problems were the most likely to experience the pain.

So why haven’t you heard of this nocebo effect before? Here’s why:

Despite the smattering of doctors’ anecdotal reports and a few modest clinical studies, research on the phenomenon has not been robust, mostly for ethical reasons: Doctors ought not to induce illness in patients who are not sick.

See full article (found via A.Word.A.Day).

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