10 Interesting Facts About the Placebo Effect

  1. Given a sugar pill (which has no physical effect) people with certain conditions not only report feeling better, but see actual improvements in their condition.
  2. Called the dose-response placebo effect, given two sugar pills, people report twice the benefit of one sugar pill (Demonstration to medical students of placebo responses and non-drug factors, Blackwell, 1972).  Interestingly, the Blackwell study also showed that pink placebo pills worked better as a stimulant and blue placebo pills worked better as a relaxant. There have been multiple other studies demonstrating this effect. See also Shapiro (1970) and the work by Moerman where he looked at clinical trials with ulcer treatments.
  3. If someone believes a placebo has a negative effect, they can experience that negative effect.  This is called a nocebo. (Magne Flaten, Terje Simonsen, and Harald Olsen, “Drug-Related Information Generates Placebo and Nocebo Responses That Modify the Drug Response,” Psychososomatic Medicine, 61, no. 2 (1999): 250-255)
  4. If a sugar pill is described as a muscle relaxant it will cause muscle relaxation.  If the same type of sugar pill is described as causing muscle tension, it will produce muscle tension.(Placebo-induced side effects. Shapiro, Arthur K.; Chassan, Jacob; Morris, Louis A.; Frick, Robert, Journal of Operational Psychiatry, Vol 6(1), 1974, 43-46)
  5. Placebos can produce the same side-effects that the real drug the person thinks they’re taking would also produce. (Asbjørn Hróbjartsson, and Peter C. Gøtzsche, “Is the Placebo Powerless? — An Analysis of Clinical Trials Comparing Placebo with No Treatment,” The New England Journal of Medicine, 344 (2001): 1594-1602, 10.1056/NEJM200105243442106)
  6. When conducting a study, it is an error to assume that your treatment produced the improvement and everyone seeing improvement under the placebo are “only” experiencing placebo effects.  It could very well be that everyone who experience an improvement were experiencing a placebo effect. (Asbjørn Hróbjartsson, and Peter C. Gøtzsche, “Is the Placebo Powerless? — An Analysis of Clinical Trials Comparing Placebo with No Treatment,” The New England Journal of Medicine, 344 (2001): 1594-1602, 10.1056/NEJM200105243442106)
  7. Saltwater placebos administered via syringe are more effective than sugar pills. The original study is by Traut & Passarelli (1957). There’s been follow up studies since then, including “Do medical devices have enhanced placebo effects?” by Ted J Kaptchuk, Peter Goldman, David A Stone, William B Stason
  8. Pacemakers improve heart function after they’ve been put in, but before they’ve been switched on. (Placebo effect of pacemaker implantation in obstructive hypertrophic cardiomyopathy Cecilia Linde, Fredrik Gadler, Lukas Kappenberger, Lars Rydén. The American journal of cardiology 15 March 1999 (volume 83 issue 6 Pages 903-907))
  9. Give people a sugar pill and tell them it’s a stimulant and they get stimulated.  Give people a relaxant but tell them it’s a stimulant and they get more even more stimulated.  Give people a relaxant, tell them it’s a relaxant and they have more molecules of the relaxant in their blood plasma than the people you gave a relaxant to but told them it was a stimulant. (Magne Flaten, Terje Simonsen, and Harald Olsen, “Drug-Related Information Generates Placebo and Nocebo Responses That Modify the Drug Response,” Psychososomatic Medicine, 61, no. 2 (1999))
  10. We’re still pretty confused about the placebo effect and it’s causes.  There’s a mishmash of different things going on and we’re still picking them apart. Also, it’s really hard to design studies!
  1. The human mind is a very powerful thing, and it is in control of an entire chemical factory. It has the power to create many of the effects we induce with drugs. This is why blind trials and double blind trials are so important.

    I was once told that thinking about exercise for an hour could have the same effect as actually doing that exercise for half an hour. The downside is that you really have to think about it, going though all of the motions in your mind as if you were actually exercising.