Placebos are pills or other treatments that are considered harmless and inactive. Researchers use placebos in studies to evaluate how well a treatment works. The subjects in the placebo group are considered the "no-treatment" group. The subjects getting the treatment become the "active treatment" group. Researchers then compare the results for the two groups.
Study subjects know upfront that they might be getting a placebo, and that the placebo is not expected to help. But what if your doctor prescribed a placebo to you without telling you and told you it would really help you? Would you feel deceived?
What if your doctor recommended treatments for which there is little scientific evidence, and told you it might work because other doctors and patients said they did? How would you feel about that?
Is ever okay for a doctor to prescribe a placebo treatment outside of a research study? Here's a closer look at this complicated — and tricky — issue.
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A Question of Ethics
For a placebo to work, it's long been assumed the patient must believe it is (or might be) a "real" drug. The idea is that believing a treatment will work may activate the body's own healing abilities.
The problem with prescribing a placebo in a doctor's practice (rather than in a research study) is that the doctor must deceive the patient by telling him it's real. This ethical concern is why the American Medical Association has taken the position that doctors should never prescribe a placebo outside of research settings.
So, I was surprised by the results of a 2008 survey among U.S. doctors that was published in the British Medical Journal. The researchers defined a placebo as "a therapy without known benefit for the condition to be treated but recommended primarily because the doctor believes it will enhance the patient's expectation of getting better."
The survey found that:
- Nearly half of the doctors reported prescribing a placebo several times per month.
- Over-the-counter vitamins and pain relievers represented the most commonly prescribed placebo treatments. But, 26% of the physicians reported prescribing antibiotics and sedatives as placebos. Only 5% of the physicians prescribed actual sugar pills.
- Almost two-thirds of the doctors surveyed considered placebo therapy "ethically obligatory or permissible."
- Only 5% of the physicians told their patients they were prescribing a medicine that isn't expected to have benefit (other than the placebo effect).
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Placebos Can Change Physiology
A surprising finding in placebo research is that people taking them often show real measurable improvements in a condition. Somehow, expecting that something will help seems to make a change for the better.
While the most appealing explanation is that placebos can "unleash" the body's own healing abilities, it's far from proven. In fact, there are other possible reasons why they seem to work, such as:
- The particular placebo is actually not inert. It could have an ingredient that has active, pharmacologic effects on the patient's condition.
- The condition is one that varies over time and it's just by chance that some people improve just after getting a placebo.
- The condition is one that is highly influenced by the patient's emotional state. The belief that you are getting a highly effective treatment might reduce anxiety and increase a feeling of control over the condition. These "calming" effects might reduce symptoms. If this is the mechanism behind the placebo effect (rather than the body's natural healing capacity), placebo therapy may help conditions with subjective symptoms (such as irritable bowel syndrome or fibromyalgia) more than diseases such as an infection or cancer.
Should a doctor count out placebo therapy when it can be so effective and is typically safer than most drugs in common use? Even if a placebo worked, isn't it better for a doctor to be honest with a patient than to prescribe something under false pretenses?
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Should the Patient Decide?
One approach to the ethical concerns over placebo use is to tell the patient that he is (or might be) getting a placebo.
The doctor would ask each patient if it would be acceptable to sometimes prescribe a placebo and at other times prescribe an active medicine. The patient would not be told which type of medicine is prescribed at any given time but would know there was always the possibility their prescription was inactive. I can see how this would raise a lot of other questions:
- Would it undermine treatment to have patients guessing which of their treatments were "real" and which were not?
- Would patients feel coerced to accept this arrangement rather than disappoint their doctor?
- What if the condition is serious or even life threatening? That's no time to be wondering if the antibiotic is real!
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Disclosing Placebo Treatment
Can a placebo work if a patient knows for sure that they are taking one?
A recent study, "Placebos without Deception: A Randomized Controlled Trial in Irritable Bowel Syndrome," explored this question. Researchers told patients they were getting placebos — and they still worked. However, as the study began, study subjects were also told that "the placebo effect is powerful" and "the body can automatically respond to taking placebo pills like Pavlov's dogs that salivated when they heard a bell."
Presenting theories about the power of placebos and how they work as facts may not be entirely appropriate, in my view. Enhancing the expectation of benefit may make up for the effect of the patient knowing about the placebo. But, this may come at the price of being fully honest.
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The Bottom Line
I have never prescribed what I consider to be a true placebo, such as sugar pill (or a similar "inert" substance), while telling my patient I thought it would make him better.
But I have recommended treatments for which there is little scientific evidence and told my patients it might work (because other doctors and patients had suggested it was true). For example, quinine for night cramps is not well-supported by high-quality evidence but many people swear by it (and there are no other highly reliable treatments). In my view, the use of antibiotics, sedatives or other medicines that carry significant risks should never be used as placebos.
Has your doctor suggested that you take a placebo? Has he prescribed one without telling you? It's a tricky issue. Whatever your opinion is on the subject, share it with your doctor. And ask him to share his view with you.
Robert H. Shmerling, M.D. is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.