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The cold and flu season is coming! What to do? Take echinacea. Certainly not! Just lie to yourself – but you must be convincing for it to work. Scientists at the University of Wisconsin in Madison conducted a study (Ann Fam Med 9:312, 2011) of 719 adults who had recently begun showing symptoms of the common cold (apparently this occurs frequently in Wisconsin). The patients were mostly white females between the ages of 12 and 80 years. The scientists were interested in determining, among other biological measures, how long their symptoms lasted. For most of us who suffer these symptoms every winter this is really all that matters anyway.
The patients were randomly divided into four groups: those that received nothing at all; those that received a placebo sugar pill; those that were given echinacea but not informed of the fact; those given echinacea who were also informed of the fact. The echinacea tablets included root extracts of Echinacea purpurea and E. angustifolia. On the surface, this appears to be your standard study of an alternative cold medication with the potential for finding some interesting placebo effects. However, the investigators introduced a fascinating twist: before starting the study they identified 120 people who already strongly believed that echinacea was an effective cold medication that had helped to reduce the severity and duration of their symptoms in the past.
This is what the researchers found at the end of the study. People not given a pill of any kind tended to have the longest and most severe cold symptoms as compared to all of the other groups. For the subgroup of people who entered the study already convinced of the effectiveness of echinacea, the duration of their symptoms was much shorter (by more than a day) and the severity of their symptoms was much less whether they were given echinacea or not. It didn’t matter at all. What mattered was that they believed that they were being given echinacea. Tinker Bell was right all along – you’ve just got to believe!
For those of us who study the brain, the placebo effect is a truly amazing facility of the human mind. No treatment has ever been shown to reduce the symptoms or duration of the common cold. Colds are caused by viruses – there is nothing we can do but let the symptoms run their normal course. Apparently our brain has the ability to break that general rule of thumb. What we believe about our treatments as well as how we feel about our healthcare in general, and the people who administer it, play an important role in how we respond to the medications we take.
Finally, does echinacea actually have any beneficial effects when it’s compared against standard cold remedies? No. (Ann Intern Med 153:769, 2010). Therefore, you can save your money this winter by having someone you trust give you a sugar pill and lie to you about what’s in it. I hear that some of these newer placebos can actually grow hair and reduce nasal congestion at the same time.
© Gary L. Wenk, Ph.D., author of "Your Brain on Food" (Oxford, 2010)
