European Headache Federation recommendations for placebo and nocebo terminology

Abstract

Background and aim Despite recent publications, practitioners remain unfamiliar with the current terminology related to the placebo and nocebo phenomena observed in clinical trials and practice, nor with the factors that modulate them. To cover the gap, the European Headache Federation appointed a panel of experts to clarify the terms associated with the use of placebo in clinical trials. Methods The working group identified relevant questions and agreed upon recommendations. Because no data were required to answer the questions, the GRADE approach was not applicable, and thus only expert opinion was provided according to an amended Delphi method. The initial 12 topics for discussion were revised in the opinion of the majority of the panelists, and after a total of 6 rounds of negotiations, the final agreement is presented. Results/recommendations Two primary and mechanism-based recommendations are provided for the results of clinical trials: [1] to distinguish the placebo or nocebo response from the placebo or nocebo effect; and [2] for any favorable outcome observed after placebo administration, the term “placebo response” should be used, and for any unfavorable outcome recorded after placebo administration, the term “nocebo response” should be used (12 out of 17 panelists agreed, 70.6% agreement). The placebo or nocebo responses are attributed to a set of factors including those that are related to the medical condition (e.g. natural history, random comorbidities, etc.), along with idiosyncratic ones, in which the placebo or nocebo effects are attributed to idiosyncratic, or nonspecific mechanisms, exclusively (e.g. expectation, conditioning, observational learning etc.). To help investigators and practitioners, the panel summarized a list of environmental factors and idiosyncratic dynamics modulating placebo and nocebo effects. Some of them are modifiable, and investigators or physicians need to know about them in order to modify these factors appropriately to improve treatment. One secondary recommendation addresses the use of the terms “placebo” and “nocebo” (“placebos” and “nocebos” in plural), which refer to the triggers of the placebo/nocebo effects or responses, respectively, and which are inert agents or interventions that should not be confused with the placebo/nocebo responses or effects themselves (all panelists agreed, 100% agreement). Conclusion The working group recommends distinguishing the term response from effect to describe health changes from before to after placebo application and to distinguish the terms placebo(s) or nocebo(s) from the health consequences that they cause (placebo/nocebo responses or effects).

One of us or one of them? The effects of the model’s and observer’s characteristics on placebo analgesia induced by observational learning

“…Thus, each stimulus that accompanies the changes in pain responses of the model has the potential to become a placebo stimulus and induce in the observer placebo analgesia. This view is shared by the large body of theorists and researchers [53]. Third, the color stimuli were counterbalanced, and the control group was included in the study design.…”

“Consensus on Placebo and Nocebo Effects Connects Science with Practice:” Reply to “Questioning the Consensus on Placebo and Nocebo Effects”

“…Hardman, Hutchinson and Ongaro for their thoughtful comments [1]. We provide consensus and recommendations in our paper on how to inform patients about placebo and nocebo effects in clinical practice, and how to train clinicians in disclosing that information, based upon previous consensus papers [2][3][4]. Hardman et al claim that our recommendations are not in line with recent research that shows a disconnect between the modern scientific definition of placebo and nocebo effects and how patients and clinicians understand those effects [5].…”

“…Usage and distribution for commercial purposes requires written permission. DOI: 10.1159/000514435 treatment outcomes that cannot be attributed to active treatment components, but are elicited by positive expectations and/or the psychosocial context in which treatment takes place" [2][3][4]. Thus, our definition and recommendations encompass an integrated approach to healthcare that includes biomedical, psychological, ethical, and philosophical perspectives.…”

“…However, it is precisely this disconnect that makes our consensus statement important. For example, while patients and clinicians tend to focus on “placebos” as inert sugar pills, placebo effects are defined broadly as “positive treatment outcomes that cannot be attributed to active treatment components, but are elicited by positive expectations and/or the psychosocial context in which treatment takes place” [2-4]. Thus, our definition and recommendations encompass an integrated approach to healthcare that includes biomedical, psychological, ethical, and philosophical perspectives.…”

What Psychological Factors Make Individuals Believe They Are Infected by Coronavirus 2019?

“…Nocebos are medically inactive substances or procedures that make the individual expect unpleasant outcomes (Mitsikostas et al, 2020). The underlying mechanisms for nocebo effects are expectations and former experiences with treatments.…”