Placebos Work, Even Without the Deception

The patients were randomized to either open-label placebo pills presented as "placebo pills made of an inert substance, like sugar pills, that have been shown in clinical studies to produce significant improvement in IBS symptoms through mind-body self-healing processes” or no-treatment controls with the same quality of interaction with providers. The primary outcome was IBS Global Improvement Scale (IBS-GIS); secondary measures were IBS Symptom Severity Scale (IBS-SSS), IBS Adequate Relief (IBS-AR), and IBS Quality of Life (IBS-QoL).

The results showed that open-label placebo produced significantly higher mean IBS-GIS at both 11-day midpoint and at 21-day endpoint. Significant results were also observed at both time points for reduced symptom severity (IBS-SSS) and IBS-AR; a trend favoring open-label placebo was observed for quality of life (IBS-QoL) at the 21-day endpoint. The study was published in the December 22, 2010, issue of PLoS ONE.

"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. We told the patients that they didn't have to even believe in the placebo effect; just take the pills,” said HMS associate professor of medicine Ted Kaptchuk, MD. "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 know it is a placebo.”

The phenomenon of an inert substance resulting in a patient's medical improvement is called the placebo effect. The phenomenon is related to the perception and expectation, which the patient has: if the substance is viewed as helpful, it can heal, but if it is viewed as harmful, it can cause negative effects, which is known as the nocebo effect. The basic mechanisms of placebo effects have been investigated since 1978, when it was found that the opioid antagonist naloxone could block placebo painkillers, suggesting that endogenous opioids are involved.

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