BOULDER, Colo., July 24 (UPI) -- Patients continued to report that placebo drugs were working after being told they were not taking medications -- but only if they had believed for long enough the placebo was working prior to being told, according to a new study.
Researchers said the new understanding of the placebo effect could lead to better ways to ease addiction and aid in pain management when dealing with stronger, more addictive drugs.
"We're still learning a lot about the critical ingredients of placebo effects," said Tor Wager, an associate professor who runs the Cognitive and Affective Neuroscience Lab at the University of Colorado, in a press release. "What we think now is that they require both belief in the power of the treatment and experiences that are consistent with those beliefs. Those experiences make the brain learn to respond to the treatment as a real event."
Researchers in the study, published in The Journal of Pain, applied a hot ceramic tile to the forearms of participants in the study, leaving it there just long enough to cause pain without burning their skin.
The burns were then treated with what the participants thought was an analgesic gel and the temperature of the room was turned down, while the researchers asked each of the participants to read forms about drugs and report their medical histories.
After treating the burns with the fake analgesic at least 4 times, the researchers told participants the gel was fake. In subsequent tests after revealing the ruse, the participants still said the fake gel, which was actually Vaseline dyed blue with food coloring, eased the pain.
"They believed the treatment was effective in relieving pain," said Scott Schafer, a graduate student at the University of Colorado who works at the lab. "After this process, they had acquired the placebo effect. We tested them with and without the treatment on medium intensity. They reported less pain with the placebo."
Schafer said the findings could lead to ways of weaning people off of drugs more easily and quickly, or not using the drugs at all.
"If a child has experience with a drug working, you could wean them off the drug, or switch that drug a placebo, and have them continue taking it," Schafer said. "We know placebos induce the release of pain-relieving substances in the brain, but we don't yet know whether this expectation-independent placebo effect is using the same or different systems."