Research by the Human Pain Research Group at The University of Manchester suggests that people's responses to placebo pain relief varies according to their way of thinking.
In the study a group of 40 pain-free volunteers took part in an experiment using an artificial pain stimulus. They were led to expect reduced pain after the application of a cream which was actually a placebo. Twenty four of the volunteers initially received a moderately painful heat stimulus to both arms. The placebo cream was then applied to the skin. They were led to believe that the cream on one of their arms may be a local anaesthetic.
After the application of the cream, the intensity of the heat stimulus was turned down on one arm without informing the volunteer. Then the intensity was returned to its previous level, but ( in contrast to the 16 people in the control group) 67% of the treatment group continued to perceive the heat as less painful.
The expectation of pain relief leads to a release of endorphins, which are the brain's natural pain killers, which is likely to contribute to a sensation of reward and well-being.
There was a split in the range of responses to the placebo; a third of people reporting a reduction in the pain intensity in the "treated" arm only, a third in both arms and the last thirds intensity-ratings were not being influenced by the application of the cream. The different responses can be related to the different levels of pain relief the volunteers expected, which may have allowed their individual suggestibility to influence their assessment of the pain experience.
The findings suggest that different individuals may have different styles of placebo response, which is likely to affect how they respond to real treatments also. So, if the mind is so powerful, shouldn't we be practicing how to harness it with self-hypnosis?