Placebo and nocebo effects, positive and negative effects experienced after both real and sham interventions, putatively due to positive or negative outcome expectancies, can shape our sensory... Show morePlacebo and nocebo effects, positive and negative effects experienced after both real and sham interventions, putatively due to positive or negative outcome expectancies, can shape our sensory experience. Although placebo and nocebo effects are known to occur reliably in many individuals for sensations like pain and itch, our understanding of psychological learning processes and methodological factors that influence these effects remains limited. Chapters 2, 3, and 4 investigate this topic with meta-analysis, narrative review, and a behavioral study. Similarly, our characterization of the neural markers of nocebo effects is incomplete. A better grasp of how these effects form is necessary to contextualize them within the larger framework of bottom-up and top-down integration. Chapters 5, 6, and 7 investigate this topic in a series of EEG and fMRI studies. Advancing both psychological and neural accounts of placebo and nocebo effects will aid in applying findings from this field of study to everyday life; particularly in clinical settings, and potentially any setting in which expectations regarding one’s future experiences come into play. Show less
Carryover of previous treatment outcomes to subsequent medical treatment outcomes seems to be pervasive. The influence of a treatment history can generalize across treatments and across symptoms.... Show moreCarryover of previous treatment outcomes to subsequent medical treatment outcomes seems to be pervasive. The influence of a treatment history can generalize across treatments and across symptoms. These generalization effects in clinical practice have been studied experimentally in placebo and nocebo effects, which are beneficial and adverse effects that do not arise from active treatment components, respectively. The aim of this thesis was to answer the question of whether previously learned placebo and nocebo effects can generalize within and across somatosensory sensations. Additionally, the thesis also explored the role of individual characteristics as predictors (e.g., anxiety, stress, attention, catastrophizing) for the generalization of placebo and nocebo effects. The findings of the thesis have showed that placebo and nocebo effects can generalize within pain and itch modalities, but can not generalize from pain to itch and from itch to touch. The generalization effects of placebo and nocebo effects can not be predicted by psychological characteristics (e.g., anxiety- and stress symptoms) in healthy individuals. Moreover, the dissertation addresses the limitations of the work and directions for future research, as well as giving implications for clinic practice. Show less