Dr Bruce Moseley, an orthopaedic specialist at Methodist Hospital in Houston, TX, was convinced of the powerful effect of the human mind on healing. He recruited 180 patients with severe knee osteoarthritis and divided them into three groups, two of which underwent true surgery to clear out degenerative tissue and debris. The third group underwent a sham operation: they were surgically prepared, put under anaesthesia and wheeled into the operating room, where incisions were made in their knees, but no procedure was carried out.
Over the next two years, none of the patients knew who had received the real operations and who had received the placebo treatment, yet all three groups reported moderate improvements in pain and joint function. In fact, the placebo group reported better results than some of those who had received the genuine operation.
The mental expectation of healing was enough to marshal the body's healing mechanisms. The intention, brought about by the expectation of successful surgery, led to physical change (N Engl J Med, 2002; 347: 81-8).
The role of the mind in healing-the subject of Bryan Hubbard's cover story this month-completely baffles the medical community. Yet, it is well documented that belief in a placebo will bring about the same physiological effects as an active agent-so much so that it causes the drug industry enormous difficulty when designing trials; as so many patients report the same relief and even the same side-effects with a placebo as with the tested drug itself, a placebo is not a true control.
How can belief-and, in this case, a wrongheaded belief-affect the outcome of healing? Some clues come from intriguing brain studies showing that the electrical activity within the brain, and between the brain and other parts of the body, is identical whether we are merely thinking about doing something or actually doing it.
In weightlifters, for instance, the EEG patterns in the brain that are activated to produce specific motor skills become activated while the skill is only being simulated mentally. Indeed, just the thought is enough to produce the neural instructions to carry out the physical act.
In the case of placebos, our bodies don't distinguish between a chemical process and the thought of a chemical process.
According to a major review, the only factor for survival appears to be a belief that the therapy will work and a willingness to follow it religiously. Patients who stick to their doctor's orders fared equally well whether taking a drug or a sugar pill. In contrast, those who tended not to survive were those who were lax with their regimens, regardless of whether it was a placebo or an actual drug (BMJ, 2006; 333: 15-9).
Such studies suggest that our beliefs-about our medicine, about the outcome of a health crisis, about our connections to our place in the world-are a more powerful healer than any diet or exercise programme; they protect us against the worst toxins and the greatest adversity.
Knowing this, every doctor now has a duty to never give a negative diagnosis, and every patient has a duty to follow only the regime that he truly believes in. The thought it generates in us-whether positive or negative-is our most potent medicine. May we always use it wisely.