Mechanisms of Placebo and Nocebo

Abstract

Placebo effects can be conceptualized as the beneficial effects triggered by the psychosocial treatment context. The nocebo effect is its negative counterpart. Over the last 30 years, the knowledge of placebo and nocebo effects has increased substantially. It has become evident that placebo and nocebo effects are interesting models to understand the intricate mind-body interaction. In addition, they are essential components of any medical setting. The psychological and neurobiological mechanisms underlying these phenomena are specified. In particular, psychological mechanisms are identified as mediators of placebo and nocebo responses; indeed, cognitive and emotional processes such as expectations, self-efficacy desires, anxiety, and somatic focus but also learning mechanisms can enhance or reduce the effectiveness of a medical treatment. Furthermore, the psychosocial context triggers a cascade of neurobiological changes in the brain. The study of these phenomena has important translational implications in the clinical setting.