Pricier placebos work better?

For years, experts have known that placebos — fake injections and pills with no real medication — can improve the health of people with pain, asthma, high blood pressure and angina.

Now, they've learned that raising the price of a fake pill can make it work even better.

A report last week in the Journal of the American Medical Association shows that expectations — shaped by factors that include the price of a medication — play a key role in how we respond to pain relievers, as well our response to therapies for depression, cancer, strokes or heart attacks.

The latest report adds to a store of knowledge about placebos, a subject that has long fascinated scientists. Understanding placebos could unravel mysteries about the body's ability to heal itself, they say.

Experts do know one reason placebos work: They raise expectations. Make someone believe that a tablet will make a headache disappear, and it often does — even if it turns out to be a sugar pill.

"Expectations create a different reality for us, which we don't really appreciate," said Dan Ariely, a behavioral economist at Duke University.

Researchers typically use placebos as controls in clinical trials of medicines and other therapies. Some volunteers get the real drug, while others get identical-looking placebos. It's not unusual for placebos to work almost as well as — and in some cases better than — the drugs being tested.

In the latest study, Ariely applied electric shocks to the wrists of 80 volunteers before and after giving each one a placebo painkiller. He told half of the subjects that the pills cost $2.50 each and the other half that they cost 10 cents apiece.

About 60 percent of the 10-cent group reported pain reduction from the placebo, compared with 85 percent of the "higher priced" group. None of the test subjects, who received $30 for their trouble, actually received a painkiller.

"It says something about our expectations and how they shape reality," Ariely said. "Price is just one of the things we use to make inferences."

Experts say the results also show the importance of boosting the hopes of patients treated for a variety of ailments.

"Our response to any intervention is partly the result of the power of the intervention and partly the result of our expectations going in," said Alan Bellack, a professor of psychiatry at the University of Maryland School of Medicine.

Placebos have improved outcomes in studies of chronic pain, anxiety, high blood pressure, angina, asthma, ulcers, Parkinson's and rheumatoid arthritis, said Irving Kirsch, a psychologist who studies placebos at the University of Hull in England.

Kirsch reviewed 35 clinical trials of antidepressants, submitted by drug companies to the Food and Drug Administration, and found that placebos did just as well as the real drug with moderately depressed patients.

The review, published in February in the Public Library of Science, also found only a small, "clinically insignificant difference" between placebos and the real drugs among patients who were severely depressed. Even so, Kirsch said that patients on antidepressants should talk to their doctors before stopping them.