Ulcers, anxiety, and blood pressure 1
[N]ocebo and placebo effects are integral to all sickness and healing, for they are concepts that refer in an incomplete and oblique way to the interactions between mind and body and among the three bodies: individual, social and politic.
(Scheper-Hughes and Lock 1987)
Some years ago I reported on an analysis of 31 double-blind controlled trials of the anti-ulcer drug cimetidine (Moerman 1982). I recently reviewed those data, added to them, and repeated the process for several other conditions and drugs. The analysis of these new data materially expands and complicates the original conclusions.
The placebo effect is an important part of the human healing process that has been considered several times in the anthropological literature (Moerman 1979, 1997, 2002; van der Geest and Whyte 1989); I will, therefore, only briefly indicate some of the dimensions of the placebo effect here.
I define placebo effects as the desirable 2 psychological and physiological effects of meaning in the treatment of illness. 3 Participating in a healing process, regardless of its content, can lead to healing. While this is clearly true, it is much easier to assert than to demonstrate to a skeptic. 4 One of the clearest demonstrations comes from what is known as a “three-arm trial” of medical treatment. In such a trial, after a diagnosis, patients are randomly allocated to one of three groups. The first group typically receives some sort of (presumably) active medication. The second receives placebo treatment, (presumably) indistinguishable from the active one but lacking the item being tested. The third, untreated, “natural history” group serves to represent what happens to patients who receive no treatment. If the group receiving placebos (inert pills, perhaps) does substantially better than the untreated group, one can attribute the difference to the placebo effect. Trials of this sort show just