Placebos can be strangely effective

The following originally appeared on The Upshot (copyright 2014, The New York Times Company). Acknowledgement: Jennifer Gilbert provided assistance tracking down articles referenced in this post.

“I bet you $1,000 that if you just tell me you’re putting Demerol in my I.V. but don’t actually do it, I would still feel a lot better,” I dared the nurse.

It was a humid June night in 2013. I had just arrived at the emergency department of Mount Auburn Hospital in Cambridge, Mass., and was in the worst pain of my life. A kidney stone was scraping its way down my right ureter, the narrow tube connecting my right kidney and bladder.

Despite my anguish, I was so confident I didn’t need a narcotic painkiller that I was willing to put $1,000 on the line. The reason: I trusted the placebo effect, the relief of symptoms just by believing one is receiving helpful care. (In this case, even though I knew the nurse might be deceiving me, I was going to believe him if he said he was giving me Demerol. That’s essential for the placebo effect to work.)

My colleague Aaron Carroll wrote last week about the importance of placebo-controlled evaluation of medical treatments and devices. We need to know when medical care is better than a placebo.

In comparing a treatment with a placebo, we should also keep in mind that the placebo is not the same thing as the absence of treatment. In research settings, placebos are specifically designed to mimic treatment without the hypothesized few “active” ingredients or procedural steps. They still include a lot of components of care. (Another form of clinical trial is to compare one treatment with another or with “usual” care — the care that would be given in the absence of the treatment being tested.)

In evaluating surgical treatments, researchers go to considerable lengths to provide elaborate, sham procedures for comparison because care delivers cure by two pathways. One is through only our bodies — for instance, when surgery addresses the mechanical source of a physical problem. The other involves our minds: When we believe we are receiving helpful care, we get better. Moreover, we do so more quickly and at a higher rate than if we receive no care at all.

The question addressed by placebo-controlled trials is whether the second effect — the placebo effect that operates only through belief — is the only effect of a given treatment. Does the “active” part of the treatment do anything more? The possibility that placebos cure is therefore acknowledged and built into placebo-controlled study designs.

To be sure, some treatments are better than placebos. These cure through both pathways, including the one activated by placebos. At the same time, the placebo effect is not ubiquitous; some studies show no difference between placebo-controlled groups and no-treatment groups. Althoughsome of the ways in which placebos work are known — for instance by activating natural neurochemicals that make us feel good — we do not yet have a full explanation of when and how they do and don’t.

If placebos were always the same as no treatment, then the following findings, most of which are summarized by the emergency physician David Newman in his book “Hippocrates’ Shadow,” would be hard to explain:

  • Taking two placebo pills (e.g., sugar pills) relieves more pain or provides a greater stimulative effect or is more sedating or heals stomach ulcers more quickly (depending on the study) than taking just one.
  • Placebo pills with a brand name printed on them are more effective at pain reduction than the same pills without the brand name.
  • Patients who faithfully take placebo medication for cholesterol reduction survive longer than those who skip doses.
  • Though sham acupuncture reduces migraines as much as real acupuncture, both reduce migraines far more than no treatment at all.
  • Measurements of increased endorphins — our bodies’ natural pain relievers — have been associated with placebos’ ability to reduce pain.

The hypothesis that when we believe placebos will heal, they do, at least to some extent, is hard to reject. Perhaps for this reason, our childhoods are full of placebo effects, and as parents, we deliver them to our children. After a boy’s minor fall, which mainly hurts his pride, a bag of ice on his knee soothes even if the knee really isn’t injured. A bandage over a girl’s scrape that didn’t break the skin ends her tears. Hugs and sympathetic tones go a long way. My mother once cured one of my childhood headaches with a piece of cheese that she said some people thought effective at doing so. She made that up, but I believed her at the time. These are all placebos.

Given the strength and ubiquity of placebo effects, many physicians prescribe them. In fact, doing so was common practice before World War II, with supportive publications in the medical literature as late as the mid-1950s. This practice faded away after the rise of placebo-controlled trials that yielded treatments that were shown to be better than placebos, but it has resurfaced in new forms.

Today, the widespread use of antibiotics for conditions that don’t require them is a form of placebo prescribing, for example. Acetaminophen for back pain appears to be a placebo as well. These may help patients feel better, but only because they believe they will do so. The active ingredient adds nothing. To the extent some doctors trick patients in an effort to achieve a placebo effect, most patients don’t seem to mind. Nevertheless, deliberately harnessing just the placebo effect by prescribing a treatment that does not have any additional direct physical effect is an ethical gray area.

The lesson of placebos is simple: The mind-body connection is strong. A lot of good can come from caring and feeling cared for. Sometimes we need, and can find, additional help from surgery, medication and other therapies. But for a wide range of common problems — from earaches to knee pain to headaches — sometimes we don’t.

When a clinical trial tells us that a therapy is equivalent to placebo, that doesn’t necessarily tell us that the therapy does little; it may tell us that the placebo does a lot. The therapy merely does nothing additional.

“I’m giving you Demerol,” the nurse said. (He didn’t take the bet.)

Within seconds, the pain from my kidney stone subsided. But, in fact, I had already begun to feel significant relief from the intravenous fluids alone — just saline. My pain, I surmised, had been exacerbated by the panic of being vulnerable and at some remove from care — first at home, where the pain started, and then in the car on the way to the hospital. Just believing I was safe and in a place where any problems could be addressed went a long way.

Though the Demerol is stronger than the placebo effect alone, I may not have needed it to reduce my pain to a tolerable level. But I definitely needed and received care, and felt some relief from that alone. The placebo effect did a lot of the work.


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