The placebo effect

Placebos have been traditionally regarded as deceptive therapies and have n ot been understood in the broader context of social symbols and of interper sonal factors that surround the healing process itself. Although the power of inert substances to heal is well recognized, the placebo effect also inf luences the outcome of conventional therapies. The role of the placebo in m odern medicine is poorly defined because of a lack of a common understandin g of what the placebo effect is and because of the negative connotions asso ciated with its use. The response rate to placebo varies by illness. The na tural course of disease and patient or physician bias can be misinterpreted as a placebo response. In research, the placebo effect is therapeutic nois e to be removed by placebo-controlled trials. Few studies are designed to m easure the placebo response rate directly. Placebos are a reminder of how l ittle is known about mind-body interaction. The placebo effect may be one o f the most versatile and underused therapeutic took at the disposal of phys icians. (C) 1999 by Elsevier Science Inc. All rights reserved.