Placebo and Nocebo Effects

Although you’ve probably heard of placebo effects, it is less likely that you have heard of nocebo effects. The placebo effect occurs when an inert substance, say a sugar pill or a saline injection, has curative or beneficial effects. The nocebo effect is the opposite; merely believing that a drug has harmful effects can make you suffer them. The nocebo effect can even kill.1

The expression, “It’s only a placebo effect” has almost become a cliché. But the placebo effect is one of the most amazing effects in medicine. It underscores the role that the psychology of the mind plays in healing. No respectable research in medicine can be done without a placebo control. Otherwise the effect of whatever is being tested could be attributed to a placebo effect. Placebo effects are the rule, rather than the exception, and they can be substantial.

What is more remarkable is that placebos work even when the people receiving them know that they are placebos. In one study2 the experimental group was given placebo pills with the 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 irritable bowel syndrome (IBS) through mind-body self healing processes.” The no treatment control group had the same quality of interaction with the providers, but they were not given the placebo.

The placebo group showed significantly higher scores than the control group on the IBS Global Improvement Scale, the IBS Symptom Severity Scale, and the IBS Adequate Relief Scale.

So the placebo effect cannot be simply the result of deception. Somehow, belief, a psychological variable, affects the body.

1Marchant, J. (2011). Fool Yourself. New Scientist, 27 August, 33.

2Kaptchuk, T.J., Friedlander, E., Kelley, J.M., Sanchez, M.N., Kokkotou, E., Singer, J.P., Kowalczykowski, M., Miller, F.G., Kirsch, I., Lembo, A.J. (2010). Placebos without Deception: A Randomized Controlled Trial in Irritable Bowel Syndrome. Http://


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One Response to “Placebo and Nocebo Effects”

  1. Our Thoughts Control Our Mind « The Epigenetics Project Blog Says:

    […] Placebo and Nocebo Effects ( […]

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