Understanding the factors driving socially-induced nocebo effects

Abstract

The nocebo effect is a phenomenon that occurs when negative beliefs elicit adverse health outcomes. Problematically, recent research has demonstrated that the nocebo effect can be socially transmitted between individuals. The purpose of this project was to identify psychological mechanisms that facilitate the influence of social learning on the nocebo effect. Chapter 2 provides a systematic review and meta-analysis of the social learning nocebo literature, with results demonstrating that not only does social learning reliably induce the nocebo effect, but the size of this effect is comparable to directly conditioned nocebo effects and larger than verbally suggested nocebo effects. Outcomes also highlighted that several secondary factors predict stronger sociallyinduced nocebo effects. Chapters 3 and 4 uncovered that exposure to second-hand anecdotes of COVID-19 vaccine side effects on social media the experience of socially-induced nocebo vaccine side effects. Moreover, a host of beliefs and contextual factors, including a preference for social media for vaccine information and having friends and family who had more severe side effect experiences, increased the ability for social media exposure to garner the negative expectancies that drive the formation of the nocebo effect. Chapters 5 and 6 examined the role of interpersonal dynamics, with the former showing that the social transmission of nocebo cybersickness in online settings is mediated by negative expectancies, However, there was no overall nocebo effect found in Chapter 6. Chapter 7 tested nocebo education as an intervention to reduce socially-induced nocebo effects. Outcomes demonstrated that nocebo education can successfully reduce socially-acquired negative expectancies and anticipatory anxiety, though again no nocebo effect was found. This thesis highlights the contexts in which socially-induced nocebo effects can occur and elucidates psychosomatic factors relevant to its occurrence.