The Power of Placebos

This week's Economist reports on a recent volume of the Royal Society's Philosophical Transactions devoted to the placebo effect in medicine. The very fact that people think they are being treated has been shown in a variety of cases to improve health. This is, indeed, why clinical trials in medicine compare treatments against placebos instead of against no treatment at all. But the Economist connects additional dots in its story, because it seems that the placebo effect is almost certainly the main reason why treatments based on "complementary" or "alternative" medicine (things that are outside of modern western science) may seem to work, even when there is no scientific basis for their ability to work. The story focuses on Dr. Edzard Ernst at Peninsula Medical College in the UK.

Over the years Dr Ernst and his group have run clinical trials and published over 160 meta-analyses of other studies. (Meta-analysis is a statistical technique for extracting information from lots of small trials that are not, by themselves, statistically reliable.) His findings are stark. According to his “Guide to Complementary and Alternative Medicine”, around 95% of the treatments he and his colleagues examined—in fields as diverse as acupuncture, herbal medicine, homeopathy and reflexology—are statistically indistinguishable from placebo treatments. In only 5% of cases was there either a clear benefit above and beyond a placebo (there is, for instance, evidence suggesting that St John’s Wort, a herbal remedy, can help with mild depression), or even just a hint that something interesting was happening to suggest that further research might be warranted.

Despite this lack of evidence, and despite the possibility that some alternative practitioners may be harming their patients (either directly, or by convincing them to forgo more conventional treatments for their ailments), Dr Ernst also believes there is something that conventional doctors can usefully learn from the chiropractors, homeopaths and Ascended Masters. This is the therapeutic value of the placebo effect, one of the strangest and slipperiest phenomena in medicine.

In other words, it is not just science that matters, even if that may be the most important thing when it comes to improving your health. It is also the mental state of the patient that matters. Physicians have known this for years--the old "bedside manner" is known to be important, but it often is ignored in the application of western medicine, whereas it may be the single most important factor in alternative medicine.