Although the placebo in a clinical trial is often considered simply a basel
ine against which to evaluate the efficacy of a clinical intervention, ther
e is evidence that the magnitude of placebo effect may be a critical factor
in determining the results of a trial. This article examines the question
of whether devices have enhanced placebo effects and, if so, what the impli
cations may be, While the evidence of an enhanced placebo effect remains ru
dimentary, it is provocative and therefore worthy of further study. Suggest
ions are made, therefore, for how such an effect can be investigated withou
t violating the principles of informed consent. (C) 2000 Elsevier Science I
nc. All rights reserved.