Research by the scientists of University of Michigan says that it is possible to wish the pain away. The research suggests that just by thinking of a painkiller can trigger the brain to release neural painkillers that can soothe the pain.
The study provides the first direct evidence that the brain's own pain-fighting chemicals, called endorphins, play a role in the phenomenon known as the placebo effect — and that this response corresponds with a reduction in feelings of pain.
Previous studies at U-M and elsewhere have shown that the brain reacts physically when a person is given a sham pain treatment, which they believe will help them.
But the new study is the first to pinpoint a specific brain chemistry mechanism for a pain-related placebo effect. It may help explain why so many people say they get relief from therapies and remedies with no actual physical benefit. And, it may lead to better use of cognitive, or psychological, therapy for people with chronic pain.
The results are published in the August 24 issue of the Journal of Neuroscience.
The findings are based on sophisticated brain scans from 14 young healthy men who agreed to allow researchers to inject their jaw muscles with a concentrated salt-water solution to cause pain. The injection was made while they were having their brains scanned by a positron emission tomography (PET) scanner. During one scan, they were told they would receive a medicine (in fact, a placebo) that might relieve pain.
The researchers correlated the participants' ratings with their PET scan images, which were made using a technique that reveals the activity of the brain's natural painkilling endorphin chemicals, also called endogenous opioids.
As the researchers alerted participants that the placebo was coming, and injected the placebo dose, the amount of additional concentrated salt water needed to maintain participants' pain over time increased — indicating a reduction in pain sensitivity that the subjects were not aware of. In other words, thinking they were getting a pain drug actually allowed the participants to tolerate even more pain-inducing concentrated salt water than before.