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Placebo may not rely on deception

Patients benefit even when they know they are taking a placebo

Louise Prime

Thursday, 23 December 2010

Even when people know that they are taking a placebo rather than an active drug they perceive symptom relief, new research has shown. The study’s surprised authors report today in PLoS ONE that people with irritable bowel syndrome (IBS) felt much better after taking placebo tablets even though they were unambiguously told that the pills were completely inert.

The National Center for Complementary and Alternative Medicine and Osher Research Center, Harvard Medical School, funded the research, looking at “whether or not the power of placebos can be harnessed honestly and respectfully” – partly because nearly half of US doctors admit to using placebos without patients’ consent.

The researchers randomised 80 people with IBS to either the control group (no treatment) or to a twice-daily regimen of placebo pills. Patients were clearly told that the pills were “like sugar pills” with absolutely no active ingredient, and the tablets were even supplied in a bottle marked ‘placebo’. All patients were monitored for three weeks.

Lead author Ted Kaptchuk said: “We told the patients that they didn’t have to even believe in the placebo effect. Just take the pills.”

To his and his colleagues’ astonishment, by the end of the trial, patients taking the placebo pills were almost twice as likely as those in the control group to report adequate symptom relief (59% vs. 35%). This rate of improvement was roughly equivalent to that seen in research with the IBS drug alosetron (51%).

Author Anthony Lembo said: “I didn’t think it would work. I felt awkward asking patients to literally take a placebo. But to my surprise, it seemed to work for many of them.”

The authors acknowledge the limitations of their study, such as its small size and short duration, and the possibility that patients were hoping to please their doctors by reporting benefit. They say it means that further, larger trials are needed into the hypothesis that even fully informed patients find placebos effective.

“Nevertheless, 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. Placebo may work even if patients knows it is a placebo,” said Professor Kaptchuk.

The authors conclude: “Placebos administered without deception may be an effective treatment for IBS. Further research is warranted in IBS, and perhaps other conditions, to elucidate whether physicians can benefit patients using placebos consistent with informed consent.”

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