A Placebo May Help Even When You Know It Is a Placebo

A placebo is an inactive substance that looks like the drug or treatment being tested. It is used in what the U.S. National Institutes of Health calls the gold standard for testing treatments in people, the randomized, placebo-controlled clinical trial. People who receive a placebo sometimes get better anyway. The National Center for Complementary and Integrative Health, part of the NIH, defines the placebo effect as a beneficial health outcome resulting from a person’s anticipation that an intervention will help. You might expect the effect to vanish once people are told the truth. Research supported by the center points the other way. One study suggested that placebos may be helpful even if patients know they are receiving placebos. Another supported the idea that placebo responses may occur outside of conscious awareness. These are findings from single studies, described with the word “may”.