Placebos without the lying: that's what a group of researchers, led by Ted Kaptchuk* at Harvard, were after in a study published at the end of December. The placebo effect is well known for making people feel better when no "real" medicine has been used. It's not a measure of gullibility, but a testament to the body's power of anticipation. Just as you start to salivate before your tasty food reaches your lips, you might start to feel better simply by visiting a doctor.
If placebo weren't a medically powerful effect, trials of new drugs and treatments could just include a no-treatment group, instead of a fake-treatment group. It's assumed that people receiving the placebo treatment will show some improvement, which researchers can then subtract from the observed effect of the real treatment. (Placebo also has a black-sheep cousin called nocebo, which makes people feel worse.)
In a medical study, researchers warn patients that they may receive either a placebo treatment or the real drug. This is because doctors, reasonably, consider lying outright to a patient to be unethical. Yet half the doctors in a 2008 survey admitted to sometimes prescribing an "impure placebo" to a patient: a vitamin, sedative, or antibiotic, for example, that isn't really intended to treat the patient's condition.
Interested in harnessing the power of placebo without so much lying, Kaptchuk and his colleagues recruited a group of 80 people with irritable bowel syndrome for "a novel mind-body management study of IBS." The subjects heard a lengthy explanation from a doctor or nurse about the power of the placebo effect. They were told that the mere suggestion of treatment could cause their bodies to react "like Pavlov's dogs." Then half the patients were given a bottle of inactive pills--clearly labeled "Placebo"--and told to take them twice a day. The other half received no treatment at all.
IBS may have been a convenient disorder for studying the placebo effect, because it can only be measured subjectively. There are no medical tests for IBS, just patients' reports of certain symptoms such as constipation or diarrhea.
When the subjects returned 21 days later to rate their symptoms, the results were impressive. The subjects who'd taken the placebo pills reported a substantial--and statistically significant--improvement when measured on three different numerical scales. In fact, the authors point out that the percentage of patients reporting "adequate relief" of their symptoms after taking the placebo pill (59%) was better than in a recent trial of an actual drug called alosetron.
It will be exciting to see what future placebo studies turn up. This study was only three weeks; would the same effect hold up in the long term? Can "open-label" placebo treatments cause significant improvements in symptoms with objective measurements, too? Even if it only works for subjectively measured symptoms, an honest placebo could be promising for people suffering from fibromyalgia or chronic fatigue syndrome. Like IBS, these disorders are collections of symptoms with no established cause or treatment. Maybe the effect of the mind over the body, instead of being a secret kept by doctors, could be an empowering discovery for the chronically unwell.
*No relation to CAPTCHA, the test that makes you decipher wiggly letters in order to prove you're not a spambot.
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