Nocebo effects in health psychology

Abstract

The nocebo effect is a potentially powerful phenomenon that can result in harmful or unpleasant treatment outcomes caused by negative expectations, past experience, and other aspects of the treatment context. These aversive outcomes can cause patients to discontinue an otherwise beneficial treatment-resulting in suboptimal health outcomes, added burden of illness, reduced quality of life, and unnecessary hospitalisations, medical consultations, and increased cost for both the patient and the health care system. Much research to date has focused on the role of negative expectations in nocebo effects; this review also emphasises the more overlooked mechanisms of anxiety and classical conditioning, and how these might be usefully targeted to reduce nocebo effects. The evidence for each of these mechanisms, and their potential interactions, is reviewed. Regardless of how they develop, nocebo effects can contribute substantially to the overall burden of treatment side effects, and an overview of evidence-based interventions to reduce nocebo effects by targeting each of the underlying mechanisms is presented. Currently, no strategies are systematically applied to reduce nocebo effects, and most interventions have yet to be translated from experimental laboratory research into applied clinical settings. Future work should focus on developing and testing theoretically-based interventions to reduce nocebo effects, and on translating findings from lab-based studies into clinical practice and healthcare policy. K E Y W O R D S anxiety, classical conditioning, negative expectations, nocebo, side effects

Knowledge of the aetiology and cost of the nocebo effect is increasing, but conceptualising expectancy and partialling out misattribution remain challenges: Comment on Faasse (2019)

“…Faasse's () review synthesises recent evidence on the mechanisms of the nocebo effect, presents an updated model of the nocebo effect, and discusses evidence for promising strategies to combat the nocebo effect. A major strength of the review and the proposed model is that they expand the traditional focus on expectancy and classical conditioning (hereafter “conditioning”) as key processes underlying the nocebo effect to also include emotional processes, namely anxiety, which have often been overlooked.…”

“…Faasse's () model proposes two ways that anxiety might contribute to the nocebo effect. The first is that anxiety may be induced by negative expectations and conditioning and mediate their effects on the nocebo effect, which recent evidence increasingly points towards (e.g., Colagiuri & Quinn, ; Colloca & Benedetti, ; Woo, ).…”

“…Faasse's () review also summarises some emerging practical strategies for combatting the nocebo effect. In terms of instructional interventions, attribute framing appears to be a promising and ethical technique for reducing nocebo‐induced side effects.…”

“…Importantly, recent evidence indicates that the pre‐exposure leading to latent inhibition does not need to be deceptive in order to be effective, which ensures that latent inhibition can be implemented ethically in applied settings (Quinn, Livesey, & Colagiuri, ). As Faasse () points out, preventative strategies such as these are paramount in the context of the nocebo effect because it appears that the nocebo effect may be very difficult to disrupt once established, with evidence indicating that it is resistant to extinction (e.g., Colagiuri, Quinn, & Colloca, ).…”

“…Faasse's () review also helps to draw attention to the fact that most research on the nocebo effect has been conducted in experimental settings, with very limited translation data available. Given that research on the nocebo effect only began in earnest over the past 10–15 years, it is not entirely surprising that the majority of research in the area has been conducted in experimental settings involving healthy volunteers.…”