Ulrike Bingel
Professor of Clinical Neuroscience, University of Duisburg-Essen

Avoiding nocebo effects to optimize treatment outcomes

There is converging evidence that the occurrence of unwanted adverse events during drug treatment is highly determined by non-pharmacological effects. For instance, the majority of UAEs and symptoms reported by patients in clinical trials are not caused by the drug itself, as suggested by the fact that UAEs can also occur to a comparable degree in the placebo arm of the study. Negative expectations and negative prior treatment experiences not only determine the occurrence of side effects, but can critically impair the therapeutic efficacy of the drug itself. These negative effects on treatment efficacy and tolerability induced/driven by psychological factors are referred to as nocebo effects. Although mechanisms steering nocebo effects are much less well understood than those of placebo effects, it is evident that these effects are not the result of a report bias but have neurobiological and peripheral physiological substrates. Nocebo effects can be triggered by a variety of psychosocial and contextual factors. The mechanisms that are best supported by empirical evidence are expectancy (i.e. patients’ expectations regarding the effect of a treatment) and learning processes induced by pre-treatment experiences such as the prior occurrence of UAEs or prior treatment failure. Importantly, learning processes mediating nocebo effects do not necessarily have to be based on first-hand experience but can also be the result of social observational learning.
In my presentation I will outline the negative impact of nocebo effects on treatment outcomes and highlight potential mechanisms-based strategies to prevent or minimize nocebo effects in the clinical context.