Placebos use mind’s power
Belief can produce effects even from fake medication
It’s a fascinating story. And it might even be true. When a battlefield clinic ran out of morphine during the Second World War, a desperate nurse filled a syringe with saline solution and told a severely wounded soldier that he was getting a shot of a potent pain killer. His agony was almost immediately relieved. The amazing effect was duly noted by Dr. Henry Beecher, an anesthetist who was tending to the troops. He began to wonder to what extent the response to a medication was due to the power of belief rather than to any active ingredient.
After the war, Beecher returned to his post at Harvard and voiced criticism of the way drugs were being tested at the time. Basically, subjects were given a drug in various doses to determine its effectiveness and side effects. Beecher suggested that the only way to determine whether the effects were due to the supposed active ingredient was to study a parallel control group given a fake pill. To make such a study truly objective, he proposed that neither the subjects nor the experimenters should know who was taking what. Furthermore, he suggested that the subjects should be randomly distributed between the experimental and control groups to ensure that the groups were as identical as possible. Beecher laid out his ideas in 1955 in a paper published in the Journal of the American Medical Association titled The Powerful Placebo, the term deriving from the Latin, meaning “I will please,” which is exactly what placebos do. The article was instrumental in the U. S. Congress amending the Food, Drug and Cosmetic Act, requiring that henceforth drugs be tested in double- blind, placebo- controlled randomized trials ( RCTs).
Much has been learned about the placebo response since Beecher began his crusade. For example, the response is sensitive to cultural differences. In Germany, where people tend to worry more about low blood pressure than high, response to placebos to control hypertension is poor. On the other hand, placebo response to ulcer medications is strong, because ulcer is a commonly diagnosed and treated condition in Germany.
Anticipation of an effect is also a factor, as is illustrated by Italian researcher Fabrizio Benedetti’s classic 2003 study. Using a tourniquet, he induced severe arm pain in volunteers who were then told either that they would be given a powerful pain killer or a drug that increases pain perception. In fact all were given just a saline injection. Anticipating more pain led to more pain, anticipating relief delivered relief. Obviously, being told what to expect by a physician has an effect on what a patient experiences. This is one reason why alternative therapies with no scientific basis have success.
One of the surprising aspects of placebo- controlled trials is that over the years, the response in the placebo group has become stronger and stronger, at least in North America, as recently pointed out by McGill researcher Jeff Mogil. This may be due to the widespread advertising of drugs here, creating an impression that virtually any ailment is treatable by pharmaceutical intervention. Although in a placebocontrolled trial the subjects do not know what they are taking, they do know that they may be getting a pill with an active ingredient. They are likely to evaluate placebos higher because of the belief that they may not be taking a placebo.
The placebo also has a wicked relative, termed the “nocebo,” meaning that an expectation of side effects can increase the chance that these will be manifested. In an Italian study, subjects with or without lactose intolerance were given pills they were told contained lactose, but in fact did not. Forty- four per cent of the truly lactose intolerant subjects got diarrhea and stomach cramps. But so did 26 per cent of the subjects who had never been diagnosed with lactose intolerance. They probably thought they were being tested for signs of the disease and that was enough to cause symptoms. In another study, half the men treated with finasteride for prostate enlargement were told that erectile dysfunction was a possible side effect, while nothing about such dysfunction was mentioned to the other half. Fifteen per cent of the men who were not informed about the possibility developed erectile problems, whereas 44 per cent of the men who had been advised of the risk experienced the problem. The mind is a powerful organ. joe. schwarcz@ mcgill. ca Joe Schwarcz is director of McGill University’s Office f or Science & Society ( mcgill. ca/ oss). He hosts The Dr. Joe Show on CJAD Radio 800 AM every Sunday from 3 to 4 p. m.
Anticipating more pain led to more pain, anticipating relief delivered relief.