A Columbia professor has uncovered fresh evidence of the existence of the often-debated placebo effect. Even the professor himself, Tor D. Wager, of the Department of Psychology, was surprised by his team's findings, which were published in the Feb. 20 issue of Science .
The study showed that the human brain processes pain differently when people believe that they have been given a pain-relieving skin cream. Wager, lead author of the study, defines "placebo" as a treatment that has no direct pharmacological effect and that may influence one's experience and physiology through one's beliefs.
"Initially, I didn't believe that people would show the placebo effect, but people really do seem to feel less pain because of it," said Wager, who conducted this research while he was a graduate student at the University of Michigan.
For the study, 48 individuals were treated with either electrical shocks in 1-second intervals, or heated patches for 20-second periods. About 70 percent of the subjects said they felt less pain when a placebo skin cream was applied, as compared with an identical cream that they believed had no pain-alleviating effects. FMRI brain imaging (functional magnetic resonance imaging) showed that when the placebo skin cream was administered to subjects, the pain centers in their brains fired off fewer signals. In other words, Wager said, the more that subjects believed the story about the pain-relieving "drug," the more that brain activity in pain centers was reduced, and the more that subjects' reported pain levels decreased.
This is the first study to show that a physical measure of pain experienced in the brain is affected by placebo, Wager said. Additional research might eventually lead to new understanding of how pain can be regulated and possibly new treatments for such afflictions as depression and Parkinson's disease. The study "scratches the surface in understanding pain," said Wager, who plans to continue his placebo research at Columbia.