Expectations of pain significantly influence individuals’ pain experiences and contribute to the nocebo effect, which is defined as unfavourable outcomes resulting from negative expectations about...Show moreExpectations of pain significantly influence individuals’ pain experiences and contribute to the nocebo effect, which is defined as unfavourable outcomes resulting from negative expectations about treatment beyond any pharmacological effects. When individuals inaccurately predict pain levels, a mismatch occurs, leading to either under or overpredictions of the pain experience. These mismatches can affect pain perception and emotional states, potentially impacting treatment outcomes. The literature presents mixed findings on how these expectancy mismatches shape pain perception. Thus, our first research question aimed to replicate the nocebo effect by assessing whether higher negative expectations induce greater experienced pain. Secondly, we investigated whether a (mis)match in pain expectancy and actual pain experience predicts the nocebo effect. Healthy participants (n = 94) were randomly assigned to either a control (n = 47) or an active group (n = 47). The latter received a nocebo manipulation induced by negative verbal suggestion and conditioning through electrical pain stimulation, which produces negative expectations of pain and can induce higher pain experiences. Participants’ pain expectations of upcoming pain stimulation and actual pain experiences were measured on a numerical rating scale. RM ANOVAs and linear regression were utilised to investigate our primary and secondary research question, respectively. Our results revealed a statistically significant nocebo effect induction to electrical pain stimulation. Additionally, the active group showed overpredictions of their pain experience, while there was no significant relationship between expectancy mismatch and nocebo responses, suggesting that mismatch alone may not be sufficient to explain nocebo responses. Prior experiences of pain might predict the nocebo effect better, as they can contribute to the formation of negative expectations, increasing susceptibility to nocebo responses. In conclusion, while we replicated the nocebo effect through verbal suggestion and conditioning, expectancy mismatch alone did not predict nocebo responses. Future studies should investigate a potential non-linear relationship for the mismatch of pain expectations and pain experiences on nocebo responses and how under- and overpredictions relate to nocebo responses separately.Show less
