Abstract

Over the decades of experimentation on the placebo effect, it has become clear that it is driven largely by expectation, and that strong expectations of efficacy are more likely to give rise to the experience of benefit. No wonder the placebo effect has come to resemble a self-fulfilling prophecy. However, this resemblance is considerably exaggerated. The placebo effect does not work as strongly as it is advertised to do in some efforts to elicit it. Half-truths about the placebo effect are now in circulation, reinforced by a number of other equivocations that it seems to attract. As the deceptive use of placebos has fallen into discredit, the use of half-truths and exaggerations—neither of which is technically a deception—becomes an ever more inviting possibility. However, there are risks and costs associated with the half-truth that the doctor possesses the power to make his or her words come true by the alchemy of the placebo effect.