Implications of placebo and nocebo effects for clinical practice

Andrea W M Evers, Professor of Health Psychology and chair of the Health, Medical, and Neuropsychology unit at Leiden University, Netherlands.



Placebo and nocebo studies have evolved from predominantly methodological research into a far-reaching interdisciplinary field that is unraveling the neurobiological, behavioral and clinical underpinnings of these phenomena in a broad variety of conditions. For example, physical complaints, such as itch or pain, can be effectively altered by placebo effects, due to induction of expectations of a possible beneficial treatment outcome (“Pain already reduces when seeing the painkiller”). The same is true for nocebo effects which are induced by expectations of a possible unfavorable treatment outcome or side effects. In addition, placebo mechanisms also play a role for immune functioning through pharmacological conditioning. The results have direct implications for the treatment of many patients. Treatment outcomes might be optimized by using both conscious and automatic strategies of optimizing expectancy effects, for example, by applying conditioning principles for therapy adherence, adding environmental cues to the preferred outcome strategies or replacing regular pharmacological treatments partly by expectancy interventions. Moreover, there is an increasing demand from health professionals to develop expert recommendations about evidence-based and ethical use of placebo and nocebo effects for clinical pain practice. Results of a survey and interdisciplinary expert meeting by invitation as part of the 1st Society for Interdisciplinary Placebo Studies (SIPS) conference showed that there was consensus that maximizing placebo effects and minimizing nocebo effects should lead to better treatment outcomes with fewer side effects. Experts particularly agreed on the importance of informing patients about placebo and nocebo effects, and training health professionals in patient-clinician communication to maximize placebo and minimize nocebo effects. The expert consensus formed a first step towards developing evidence-based and ethical recommendations about the implications of placebo and nocebo research for medical practice, based on the current state of evidence and the consensus of experts. In the presentation, recent results will be presented to demonstrate the evidence for placebo and nocebo effects in various conditions as well as innovative methods to induce or change placebo and nocebo effects. Moreover, the presentation will focus on how to implement the recommendations of the expert consensus, including how to optimize conditions for educating patients about placebo and nocebo effects, and providing training for the implementation in clinical practice.