Mechanisms Involved in Placebo and Nocebo Responses and Implications for Drug Trials

Drug trials often compare active drugs with inert placebos under double-blind conditions. This standard design is increasingly being questioned in light of recent progress in understanding the mechanisms behind the placebo response.(1,2) The growing knowledge of the neurobiology of placebo is forcing us to reconsider the significance of the placebo in clinical practice, with consequent profound implications for the design of clinical trials.