For most of us, the “placebo effect” is synonymous with the power of positive thinking; it works because you believe you’re taking a real drug. But Harvard researchers are now rattling this assumption.
Researchers at the School’s Osher Research Center and Beth Israel Deaconess Medical Center (BIDMC) have found that placebos work even when administered without the seemingly requisite deception. The study appeared in the December 22 issue of PLoS ONE.
Data on the placebo effect are so compelling that many U.S. physicians—one study estimates 50 percent—secretly give dummy pills to unsuspecting patients. The ethically questionable nature of such a practice led Ted Kaptchuk, an HMS associate professor of medicine, to team up with BIDMC colleagues to explore whether the power of placebos can be harnessed honestly and respectfully.
The researchers divided 80 patients suffering from irritable bowel syndrome (IBS) into two groups: the control group, which received no treatment, and the test group, which received a regimen of placebos—disclosed as “like sugar pills”—which they were instructed to take twice daily.
“Not only did we make it absolutely clear that these pills had no active ingredient and were made from inert substances, but we actually had ‘placebo’ printed on the bottle,” says Kaptchuk. “We told the patients that they didn’t even have to believe in the placebo effect. Just take the pills.”
For a three-week period, the patients were monitored. By the end of the trial, nearly twice as many patients treated with the placebo reported adequate symptom relief as compared to the control group (59 percent vs. 35 percent). Also, on other outcome measures, patients taking the placebo doubled their rates of improvement to a degree roughly equivalent to the effects of the most powerful IBS medications.
“I didn’t think it would work,” says senior author Anthony Lembo, an HMS associate professor of medicine at BIDMC and an IBS expert. “I felt awkward asking patients to literally take a placebo. But to my surprise, it seemed to work for many of them.”
The authors caution that this study is small and limited in scope and simply opens the door to the notion that placebos are effective even for fully informed patients—a hypothesis that larger trials will need to confirm.
“Nevertheless,” says Kaptchuk, “these findings suggest that rather than mere positive thinking, there may be significant benefit to the very performance of medical ritual. I’m excited about studying this further. Placebos may work even when patients know they’re taking placebos.”