Research master thesis | Psychology (research) (MSc)
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Nocebo effects, i.e., unfavorable treatment outcomes that cannot be ascribed to active treatment components, play a key role in the persistence of physical symptoms. As conditioning is an important...Show moreNocebo effects, i.e., unfavorable treatment outcomes that cannot be ascribed to active treatment components, play a key role in the persistence of physical symptoms. As conditioning is an important factor in the induction of nocebo effects, counterconditioning may be a promising mechanism to reduce these effects. However, it is unknown whether conditioning and counterconditioning can effectively induce and reduce nocebo effects on a clinically-relevant pain modality, such as pressure pain. Furthermore, while various personality factors have been associated with susceptibility to the nocebo effect, little is known about a potential interplay between them. In the current study, we investigated in healthy participants whether nocebo effects on pressure pain can be induced, via open-label conditioning, and reduced via counterconditioning and whether counterconditioning is more effective than extinction. All procedures were combined with open-label verbal suggestions. Additionally, we investigated the roles of body vigilance, catastrophizing, and pessimistic tendencies in the induction and reduction of the nocebo effect. We found that conditioning could effectively induce a nocebo effect on pressure pain. Moreover, both counterconditioning and extinction were able to reduce the nocebo effect but counterconditioning was more effective. In addition, we did not find a significant relationship between the personality factors and the nocebo effect and its reduction. These findings indicate that counterconditioning with verbal suggestion is a promising strategy for reducing nocebo effects. Future research should investigate the generalizability of this method to a clinical population and should further examine the role of personality factors in nocebo effects.Show less
Background: Studies in the last couple of years revealed that nocebo effects, i.e., adverse treatment outcomes which are not caused by the active components of the treatment itself, negatively...Show moreBackground: Studies in the last couple of years revealed that nocebo effects, i.e., adverse treatment outcomes which are not caused by the active components of the treatment itself, negatively influence therapy results. Placebo effects could occur when participants know a treatment is inactive (i.e., open-label design). However, more research is needed to understand the effects of an open-label design with verbal suggestion on the nocebo effect. Secondly, more research is needed to detangle which personality factors are relevant to the nocebo effect. Objective: The present study aimed to investigate whether open-label conditioning combined with verbal suggestion can induce a nocebo effect. Furthermore, this research aimed to explore the relationship of pain catastrophizing and the nocebo response and investigate if this relationship was mediated by state anxiety. Design: A single blind, within-subjects, open-label design was used for the study. The nocebo effect was induced in 82 healthy females, via conditioning and verbal suggestion, using pressure pain. Before the experiment, participants filled in the State-Trait Anxiety Inventory and the Pain Catastrophizing Scale to measure state anxiety and pain catastrophizing. Results: This study showed that open-label conditioning combined with verbal suggestions was effective in inducing increased pain after the conditioned stimulus when compared to the control stimulus, indicating the presence of the nocebo effect. No significant results were found to support the hypothesis that pain catastrophizing is correlated with the nocebo effect, nor that this effect is mediated by state anxiety. Conclusion: These findings highlight the possibility to investigate the nocebo effect using a more ethical open-label design. Future research can implement an open-label approach when designing treatment procedures in a clinical population. More research is needed to clarify the role of pain catastrophizing and state anxiety on the nocebo effect.Show less
