Take Two Sugar Pills: Explaining the Placebo Effect

Walter Brown had gotten over a bad bout of flu, but couldn’t get rid of his nasty cough. As it persisted over many weeks, he began to worry and called his doctor. In an upbeat and authoritative way, the doctor told Brown that coughs are normal after the flu and prescribed a cough suppressant. But if the problem continued, the doctor said, he should call back. Brown immediately felt relieved, and the cough bothered him less throughout the day, though he says he probably coughed just as much. The reassuring words from his doctor and the feeling that he was in control, he surmised later, contributed to his improved sense of well-being.

Brown is a psychiatrist who teaches at Tufts School of Medicine and also at Brown University. For the last 25 years, he has been studying the placebo effect, an improvement in health not attributable to active medication. In his new book, The Placebo Effect in Clinical Practice (Oxford University Press), he explores the phenomenon and its implications.

Tufts Now: What is the placebo effect?

Walter Brown: It is the improvement that occurs in people who are ill in which they get everything other than a specific, active treatment. It’s a response to all the common factors of treatment, which include going to an expert, having expectations for recovery and getting access to various kinds of healing rituals. It’s the response to really everything that goes on in treatment, with the exception of an active drug. Of course, a narrow—and common—definition of the word placebo itself is a capsule that contains no active pharmacological agent.

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Walter Brown

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Walter Brown

How does the placebo effect work?

Expectation is probably the most widely researched mechanism of the placebo effect. In essence, when people anticipate what they’re going to experience as a result of medical treatment, that expectation has a tremendous influence on what happens. Alcohol and caffeine are the most studied substances in a lab setting, and both show that if someone thinks they are getting alcohol or coffee, they react as if they had.

With alcohol they will undergo all of the psychological and physiological changes that occur, including getting drunk. With caffeine, if someone is told they have caffeinated coffee, they have all the effects of the stimulant, including increases in alertness and decreases in reaction time, even if the coffee is decaffeinated.

The placebo effect has been shown time and time again. It’s also true in a clinical context: if someone believes they are given a pain medication or an antidepressant, they tend to experience the effect of such drugs, even if they haven’t been administered.

What else helps it work?

Conditioning is also a factor. The Russian physiologist Ivan Pavlov showed us that when you present a dog with food, it starts to salivate. He discovered that the salivation occurs even before the food shows up, so that when a trainer rings a bell when giving food, all it takes is the stimulus of the bell to bring on the salivation response. It also occurs with drugs. If you give rats an amphetamine-like drug that increases their activity, after a couple of injections, you can give them an injection with saltwater and it has the same effect.

The same thing can happen with people. If you’ve taken a pill in the past that took your pain away, just taking a pill that looks like that first one, even if it contains no pain medication, may bring relief.

Are there some conditions that respond better to placebos than others?

It’s worth dividing what people suffer from into illness and disease. Illness has been conceptualized as the kind of subjective discomfort that goes along with the disease—the pain, discouragement, generally lousy feeling and worry. Disease is what a doctor sees on an X-ray or a scan, such as a broken bone or a tumor. Placebos are almost invariably helpful with illness—the suffering people undergo—and are less likely to have an effect on actual disease progression.

There was a study a year ago that showed this very well, dealing with patients who had asthma and were given either placebos or active drugs. Those who got placebos said they felt better and their breathing was better. But it was only the actual asthma drug that showed an objective change in the state of the airways.

What are the implications?

The implications are profound. In some instances, you can substitute placebos for active drugs and get the same result as you would from taking the active drug. This would reduce the expense of drug treatment regimens and the incidence of side effects.

Will a placebo still work if people are told that’s what they’re getting?

A lot of people think it won’t, because expectation is so important. But there have been studies that show if you tell patients openly they are getting a capsule or tablet without medicine, and if you also tell them that other people often improve with this kind of treatment, because it may stimulate the body’s own self-healing processes, they get better.

Do doctors administer placebos?

Surveys show that well over 50 percent of doctors use them fairly regularly. What they give people is an active treatment, a vitamin or low dose of something, knowing it has no inherent therapeutic effect, but they do it because the patient wants something. They use it as a placebo, but it’s not a sugar pill. And doctors give them out inadvertently all the time. Any time a doctor gives a patient an antibiotic when they have a virus, they are basically being given a placebo. Sometimes doctors do it thinking it may be helpful, but often it’s to satisfy the patient’s request for something.

What does current research tell us about placebos?

Because we can now take images of the brain, we can see that when people think they are being given a pain medicine, for example, they undergo some of the same brain changes that occur when an actual pain medication is prescribed. This has really changed a lot of the ways people think about placebos. In the past, it was thought that if people said they were feeling better after getting placebos, they were imagining it or telling their doctors what they thought they wanted to hear. But now you can show there are actual changes in the brain.

How do you think the medical profession should use placebos?

I think fostering the placebo effect takes time. Doctors need to spend time with patients, listen to them talk about their symptoms and go through an evaluation and prognosis. All this contributes to people feeling better, but those things take time, and doctors are under a lot of time pressure. And I think a lot of health-care providers just don’t know how to harness the placebo effect. Health professionals need to be taught about its value and how to make use of it to enhance treatment.