Would you knowingly take a placebo?

Consumer Reports News: December 29, 2010 09:08 AM

You're in your doctor's office. As you explain the symptoms of your illness, and describe how miserable you're feeling, your doctor listens carefully. When you finish talking, your doctor nods sympathetically, then hands you a bottle of pills. It says "placebo" on the label. "They're basically candy," your doctor says. "Take one twice a day. You'll soon feel better."

Most people's reaction would be to ask if their doctor was for real. But in a new study, where researchers openly gave people with irritable bowel syndrome placebo pills, the inactive treatment actually did seem to work.

The researchers, based at Harvard Medical School, were quite open about what the pills were. "These are placebo pills," study participants were told, "made of an inert substance, like sugar pills." The pills were made from microcrystalline cellulose, a plant product that can't be absorbed by the body.

The study looked at 80 people—mostly women—with irritable bowel syndrome. After three weeks, people who'd been taking placebo pills gave their symptoms an average rating of "slightly improved." The average rating given by people who'd had no treatment was "no change." The improvements people saw were comparable with those achieved by the drugs currently used to treat IBS.

Although placebo treatments are often used in clinical trials, they're controversial in everyday medical practice. The American Medical Association warns that "the use of a placebo without the patient's knowledge may undermine trust." Even so, about half of American rheumatologists admit to prescribing drugs that are unlikely to help a patient except through the placebo effect.

The ethical dilemma that doctors face is that prescribing a placebo can mean deceiving the patient. The new study suggests that doctors could help patients take advantage of the placebo effect without misleading them.

Harnessing the placebo effect could be valuable, because it's much more than the power of positive thinking. True, positive expectations and reassurance from a medical practitioner may form part of the placebo effect. However, there's also research suggesting that a placebo can somehow lead to physical changes in the body. In one trial, placebo shots mimicked the effect of drugs for Parkinson's disease and increased levels of dopamine in the brain. Another study found that having a pacemaker helped people's chest pain even before it had been switched on, perhaps because people were less anxious and had lower levels of stress hormones after surgery.

The new study only looked at people with irritable bowel syndrome, for which some treatments do seem to work. But there are lots of conditions where drugs are of doubtful benefit, such as coughs, colds, and milder cases of depression. If your doctor suggested a placebo might help you, would you be willing to try one?

What you need to know

In a small pilot study, placebo pills helped people with irritable bowel syndrome feel better than no treatment at all. People rated their symptoms as having improved even though they knew they'd been taking a pill that didn't contain any medication. If you have IBS and prefer the idea of taking real medications, anti-spasmodic drugs and fiber supplements are among the more promising options.

—Philip Wilson, patient editor, BMJ Group

ConsumerReportsHealth.org has partnered with The BMJ Group to monitor the latest medical research and assess the evidence to help you decide which news you should use.

See our ratings of treatments of irritable bowel syndrome (available to subscribers).

—Joel Keehn