Enhancing the Placebo

Enhancing the Placebo
By OLIVIA JUDSON
The placebo effect is, potentially, one of the most powerful forces in medicine. The challenge is to harness that power in a reliable and systematic way.

First, what is the placebo effect?

It’s the improvement in health that some patients experience because of the feeling that they are receiving medical care. A classic example comes from drug trials. Suppose patients are randomly divided into three groups: those who get no treatment, those who get the drug that’s being tested, and those who get the placebo treatment — typically a pill that looks and tastes like the drug, but doesn’t contain it, or any other active ingredient.

The idea is that the “no treatment” group shows how many people would have gotten better by themselves; the “placebo” group shows any effect of participating in medical rituals (like taking pills); the “drug” group shows any effect of the drug over and above the effect of medical rituals. Simple.

Or not. Different studies of the placebo effect report wildly different results. One survey of 117 trials of two ulcer drugs found that, depending on the trial, patients in the placebo group had anywhere from zero to a 100 percent recovery rate.

The drugs also varied in their effectiveness from one trial to the next; sometimes patients on the placebo did better than those on the drug. Intriguingly, the results varied from country to country, with Brazilians showing no placebo effect and Germans having a strong one. Why? No one knows, but it doesn’t appear to be because of anything inherently German: trials of drugs for hypertension found a weaker placebo effect in Germany than in other countries.

The problem is that humans are not machines, and emotions are not abstractions. Hope and expectation, anxiety and fear, trust and suspicion — these cause physiological changes in the brain that can interact with drugs, changing their effects.

This is even true for a drug like morphine. Yes, it’s a powerful painkiller. But it’s far more powerful if a doctor marches in, tells you he’s going to give you morphine, and injects you, than it is if it is administered secretly by a hidden machine.

Differences in hopes and fears, and the resulting physiological changes, may explain why the placebo effect varies so much: individual experiences matter. Some people are more anxious than others, or may find the thought of a particular disease especially alarming. Moreover, in different cultures, similar diseases may be treated with different degrees of gravity.

Expectations around medical rituals may also explain why placebos tend to be more powerful if the pills are expensive or you take them several times a day; why injections and exotic machines are more powerful than pills; and why surgery is more powerful than injections. (In placebo surgery, the patient is anaesthetized, cut, and sewn back up again, but no manipulation is done. For obvious reasons, there have been few tests of this. But when it has been done, it has often produced good results for the patients.)

However, the most reliable source of a strong placebo effect appears to be: the doctor.

Placebo treatments are more powerful if your doctor believes in them. They are also more powerful if the doctor tells you so. In one study, for example, patients who had just come out of surgery were given a saline infusion, and — whenever they asked for it — the pain killer buprenorphine. However, some patients were told the saline infusion was a powerful painkiller, others that it might be one, while a third group wasn’t told anything. Over the course of three days, those in the “know-nothing” group asked for more buprenorphine than those in the “maybe” group, who in turn asked for more than those told they were getting a real drug.

Which highlights a problem. Since deception of patients is unethical, some argue that the placebo has no place in the actual practice of medicine.

But the matter is more nuanced. As the morphine example shows, the placebo effect also enhances “real” treatments. So the key is to figure out how to maximize that enhancement without lying. One idea would be to deliberately increase the element of formal ritual in medicine. Studies of “alternative” therapies show that strong placebo effects can be induced by ritual. Indeed, in mainstream medicine, surgery is the treatment most surrounded by ritual; perhaps this is one reason it appears to be the most powerful placebo.

To be sure, many questions still need to be answered. But one thing is clear. It’s time we stopped treating the placebo effect as a nuisance — something that rational humans shouldn’t have. Instead, we must learn to purposefully enhance its power.

(For details on sources, please see the notes attached to the online version of this column.)

Olivia Judson, a columnist for nytimes.com, is a research fellow in biology at Imperial College London.