A recent Wall Street Journal piece http://online.wsj.com/article/SB1000142405297020472 examined the nature of the placebo effect. We have touched on this in the past but an up to date review is always welcome.
The conclusion is simply this–the mind has an enormous impact on how disease states affect us. This is a confirmation of the integration of our thoughts and feelings with our physical body.
What may be less clear is whether placebos produce physical changes in the structure of disease states or just our perception of suffering.
The WSJ article by Shirley S. Wang pointed out that the placebo effect worked even when patients were told they were receiving one.
Of interest was a study in which hotel-room attendants were told that they were getting a good work out lost weight and had lower blood pressure. In the group who were not told, no changes occurred. Neither group reported changes in diet or exercise.
Even satiety after meals depended upon how many calories the participants were TOLD they consumed rather than the actual amount. This was not merely a psychological effect. Serum ghrelin (a gut peptide involved in feelings of satiety) levels actually changed.
Conditions such as depression and irritable bowel syndrome respond so well to placebos that pharmaceutical companies have difficulty demonstrating their billion dollar drug's effectiveness to the FDA.
When Wang asks whether placebos work on the actual condition or on the perception of success, she quotes Dr. Kaptchuk's work with asthma patients. He concluded that it was more perceptual than physiologic.
That conclusion is not even consistent with Wang's report itself. She had already noted that serum ghrelin levels responded to placebo didn't she?
Also the entire field of PNI (psychoneuroimmunology) is based on the notion that psychological factors cause physiologic changes in our body's immune system which are measurable and quantifiable. So this is more than perception (not that that is irrelevant either).
The mind does change the body, as the body affects the mind.
Although chronic stress clearly impairs our immune system through a variety of neurochemical pathways, the good news is that we can do something about it.
Meditation, exercise, prayer, positive affirmations, humor, companionship all alter our state of mind in a positive direction.
Both our personal experiences and experimental science confirm that truth.