Alexithymia, not fibromyalgia, predicts the attribution of pain to anger-related facial expressions

Background: Fibromyalgia (FM) is a syndrome characterized by chronic, widespread musculoskeletal pain, occurring predominantly in women. Previous studies have shown that patients with FM display a pattern of selective processing or cognitive bias which fosters the encoding of pain-related information. The present study tested the hypothesis of an increased attribution of pain to facial expressions of emotions (FEE), in patients with FM. As previous studies have shown that alexithymia influences the processing of facial expressions, independent of specific clinical conditions, we also investigated whether alexithymia, rather than FM per se, influenced attribution of pain to FEE. Methods: One hundred and twenty-three women (41 with FM, 82 healthy controls, HC) were enrolled in this cross-sectional case-control study. We adopted two pain-attribution tasks, the Emotional Pain Estimation and the Emotional Pain Ascription, both using a modified version of the Ekman 60 Faces Test. Psychological distress was assessed using the Hospital Anxiety and Depression Scale, and alexithymia was assessed using the Toronto Alexithymia Scale. Results: Patients with FM did not report increased attribution of pain to FEE. Alexithymic individuals demonstrated no specific problem in the recognition of basic emotions, but attributed significantly more pain to angry facial expression. Limitations: Our study involved a relatively small sample size. The use of self-reported instruments might have led to underestimation of the presence of frank alexithymia in individuals having borderline cut-off scores. Conclusions: Alexithymia, rather than FM per se, plays a key role in explaining the observed differences in pain attribution to anger-related facial expressions.