Pain relief effectiveness down to mind-set?
December 2006Research by the Human Pain Research Group based at Hope Hospital suggests that people's responses to placebo or ‘dummy’ pain relief depends upon their way of thinking.
Lead researcher Alison Watson said: "All medical treatments involve a placebo element; the psychological suggestion that it is going to work. So we theorised that a proportion of any treatment's effectiveness would relate to how much we wanted or expected it to work, or trusted the person administering it."
24 pain-free volunteers were given a moderately painful heat stimulus to both arms. A placebo cream was then applied to the skin, but they were led to believe that the cream on one arm 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. It was subsequently returned to its previous level, but - in contrast to the control group - 67% of the treatment group continued to perceive the heat as less painful.
Alison said: "The expectation of pain relief leads to a release of endorphins, the brain's natural pain killers, which is likely to contribute to a sensation of reward and well-being. Interestingly though, there was an exact split in the range of responses to the placebo.
"A third of people reported a reduction in the pain intensity in the 'treated' arm only, another third in both arms, and the remainder's intensity-rating wasn't influenced by the cream. These 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.
"If different individuals have different styles of placebo response, this is likely to affect how they respond to real treatments too. Understanding these differences could better inform the way doctors and nurses provide treatments, and facilitate more effective clinical trials for the development of new pain killers.
"A further, exciting possibility is that we could develop talking and drug-based therapies to enhance people’s response to placebos, as a method of treating pain."
