[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]

Studies in recent decades have confirmed the efficacy of placebos—inactive drugs that patients believe are medicinal—in everything from depression to cancer.

But going beyond an inactive drug alleviating an active disease, it turns out the extraneous items involved in ingesting a sham pill can have just as much success as the placebo drug. Think the white coat on a doctor, the kind of liquid one uses to swallow the pill, the needle used to inject a drug. In a 2008 study at the University of Essen in Germany, 30 subjects, who were allergic to dust, washed down allergy pills for five days, with a strange-tasting drink. (The allergy pill inhibited the annoying histamine reaction.) Later, 11 subjects received the strange drink but with an inactive placebo pill. The others received just water and either the active drug or placebo.

Those subjects who got the strange drink with placebo, had nearly the same reduction in allergy symptoms as those who received the active pill! Those who drank water with the placebo had no such response.

Researchers have narrowed down the neurological basis for conditioning like this. The three critical brain areas involved are:  the insular cortex, the amygdala and the hypothalamus. More remarkable still, through various studies at the University of Turin Medical School, researchers confirmed that conditioning has a stronger effect on our involuntary physiology processes, like an allergic reaction, than our conscious belief in a placebo pill does.

For more on placebos and other conditioning stories, please stay tuned for the article, "Cure in the Mind," in the upcoming issue of Scientific American Mind.

—Christie Nicholson

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