Supplementary Material for: Interoceptive Sensibility, Alexithymia, and Emotion Regulation in Individuals Suffering from Fibromyalgia

Introduction: People suffering from fibromyalgia syndrome report various difficulties in emotional processing, possibly resulting from changes in bodily perception (interoception). In our study, we investigated the relationships between interoceptive sensibility (IS) and two disease-relevant emotional components (alexithymia and emotion regulation) in fibromyalgia sufferers compared to healthy individuals. Methods: Fifty-five fibromyalgia sufferers and 55 healthy individuals, matched with regard to age and gender, participated in our cross-sectional study. All participants completed the following self-report measures: the Multidimensional Assessment of Interoceptive Awareness, the Toronto Alexithymia Scale, and the Emotion Regulation Skills Questionnaire. Depression and anxiety scores served as confounding variables. Results: Fibromyalgia sufferers reported a stronger tendency to note as well as to avoid (unpleasant) body sensations. IS and psychopathology each explained about thirty percent of the variance in emotion regulation in fibromyalgia sufferers. Alexithymia was related to IS and emotion regulation in controls but not in fibromyalgia sufferers. Conclusion: Disturbances in interoception could be seen as the starting point of emotional difficulties in people with fibromyalgia. Following the fear-avoidance-model, experiential avoidance may restrict patients’ ability to adaptively regulate emotional states, possibly initiating a vicious cycle of psychological distress and pain.