Preliminary investigation of disorders of gut–brain interaction and their associations with psychological flexibility and daily functioning in people with fibromyalgia

Background: A substantial proportion of people with fibromyalgia also experience comorbid disorders of gut–brain interaction (DGBIs), which can lead to considerable personal and societal burdens. However, evidence regarding the implications of this co-morbidity remains limited. The aim of this study was to investigate the occurrence of DGBIs in fibromyalgia, potential consequences for people when this happens, and a process called psychological flexibility (PF) that might help.

Methods: 395 adults with fibromyalgia completed an online survey and were included in the analyses. Analyses included group comparisons, correlations, and mediation models.

Results: 79.2% of the participants reported having at least one DGBI. Participants with multiple DGBIs reported significantly worse daily functioning, compared with those without any DGBI. More severe gastrointestinal (GI) symptoms were correlated with more severe depression and worse daily functioning (r=.41 to .56, p<.001). PF statistically mitigated the relationship between GI symptom severity and depression and daily functioning (b=.05 to .13).

Conclusions: While people with comorbid fibromyalgia and DGBIs report worse functioning, PF appears to modestly buffer the relationship between DGBI symptom severity with mood and daily functioning. Therefore, treatments that target PF, such as Acceptance and Commitment Therapy (ACT), may help address the challenges faced by this population. Longitudinal studies with experimental designs are needed to further explore the mediating role of PF and the utility of related treatments for this population.

© 2026 The Author(s). European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC ®.
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