Responsiveness to Direct Verbal Suggestions and Dissociation Independently Predict Symptoms Associated with Environmental Factors

Abstract

Symptoms associated with environmental factors (SAEF; also known as idiopathic environmental intolerance) include the presentation of various common symptoms that are causally attributed to normally benign environmental triggers, such as electromagnetic fields, odors, and chemicals. SAEF are typically conceptualized as psychogenic in origin, and multiple models have proposed that dissociation and responsiveness to suggestions may contribute to the manifestation or expression of these symptoms. This preregistered study sought to characterize these variables’ independent and interactive predictive utility. Participants (<i>N</i> = 294) completed psychometric measures of dissociative tendencies, trauma, SAEF, and a behavioral scale indexing responsiveness to direct verbal suggestions. Moderation analyses were used to evaluate predictions derived from different models regarding whether these variables would uniquely and interactively predict individual differences in the reporting of SAEF. Responsiveness to verbal suggestions individually predicted SAEF, but no clear evidence was observed for an interaction with dissociation or trauma. Dissociation similarly individually predicted SAEF with additional evidence that this association was moderated by trauma such that the positive association between dissociation and SAEF was only significant in those with moderate-to-high trauma exposure. These results align with the proposal that environmental factors may function as suggestions that trigger involuntary symptoms in some individuals. Our findings further suggest that among individuals with a history of trauma exposure, those with dissociative tendencies may be at an increased risk of experiencing SAEF.

Trait responsiveness to verbal suggestions predicts nocebo responding: A meta-analysis

“…These data complement previous systematic reviews and meta-analyses showing the clear efficacy of verbal suggestion in the induction of nocebo responses (Petersen et al, 2014; Rooney et al, 2023; Webster et al, 2016) but bridge a gap in the literature by illustrating the significant moderating influence of trait responsiveness to suggestion on nocebo responding. This aligns with a wealth of data showing that trait suggestibility is a reliable predictor of responses to suggestion-based interventions (Jensen et al, 2023; Milling et al, 2021; Thompson et al, 2019) but also seems to function as a risk factor for conditions and symptoms adjacent to nocebo responding including functional neurological disorder (Wieder et al, 2021), mass psychogenic illness (Sapkota et al, 2020) and symptoms associated with environmental factors (idiopathic environmental intolerance) (Stein et al, 2023).…”

“…Items are rated in a binary fashion (0=No; 1=Yes), and computed into a percent score. Items are based on Cochrane criteria and PRISMA recommendations (adapted from (Stein et al, 2023; Thompson et al, 2019; Wieder et al, 2021).…”

“…As such, the capacity to respond to verbal suggestions represents a promising candidate predictor of nocebo responding. Moreover, elevated suggestibility is a hallmark feature of a range of phenomena germane to nocebo responding, such as the experience of symptoms attributed to environmental factors (idiopathic environmental intolerance) (Stein et al, 2023), functional neurological disorder (Bell et al, 2011; Fiorio et al, 2022; Wieder et al, 2021), and mass psychogenic illness (Sapkota et al, 2020). Additionally, trait empathy is weakly associated with nocebo responding (Meeuwis et al, 2023), and moderately associated with suggestibility (Wickramasekera & Szlyk, 2003).…”