Placebo controls in randomized trials of acupuncture.

Considerable intellectual and practical effort has been expended on designing and evaluating placebo controls in acupuncture studies. Somewhat less attention has been paid to the question: Why use a placebo in a randomized trial of acupuncture? This is partly because placebo controls have generally been seen as an inherent part of randomized trial methodology. As a result, most acupuncture trials have included a placebo-control group. A large number of different placebo techniques have been used in these trials. The design and choice of placebo techniques has typically depended on purely theoretical considerations, without empirical validation of physiological inactivity and psychological credibility. Principles can be developed for deciding whether to use placebo or another form of control in a randomized trial. These include issues of ethics, practicality and methodology. Such principles apply regardless of the intervention; they can and should be applied to acupuncture research.