The silent healer: the role of communication in placebo effects

Placebo effects have an ambiguous reputation, as they are associated with sham treatment and deceit on the one hand and as interesting phenomena, which might be clinically relevant on the other. The goal of this paper is to demonstrate that placebo effects are relevant and can be used as an effective part of many treatments by using communication targeting placebo effect mechanisms. We examined the history of placebos and the placebo effect, addressing common misconceptions and disentangling ambiguities. We then reviewed whether the placebo effect can be robustly shown in the current literature, and zoomed in on the plausible mechanisms (conditioning, expectancies and affect manipulation) through which the placebo effect might be produced. Observing the link with the doctor-patient communication literature, and pleading for a better integration of the two research traditions we conclude by setting out a research agenda for testing the role of communication in placebo effects.