The Relationship Between Pain and Depression in Fibromyalgia: Structural Equation Modeling and Network Analysis

Fibromyalgia (FM) is characterized by chronic pain, fatigue, and sleep disturbances, which often coexist with psychiatric symptoms, complicating its clinical profile. This study aims to investigate the relationships between FM components and psychopathological correlates, focusing on the central role of depression within the FM symptom network. A cross-sectional study was conducted on 50 outpatients diagnosed with FM according to the American College of Rheumatology 2016 criteria. Participants completed a comprehensive battery of validated assessment tools measuring FM components (pain, fatigue, and sleep disturbances), psychopathology (depression and anxiety), and stress-related dimensions. Structural equation modeling (SEM) and network analysis were used to explore the interplay between FM-related and psychological factors. The findings revealed a complex relationship between depression and pain in FM, with depression emerging as a central and highly connected factor within the symptom network, associated with both emotional and physical dysfunction. Fatigue was identified as a significant mediator between depression and pain, while stress, though not central, contributed to the overall symptom burden. These interactions underscore the multifaceted nature of FM, where psychological and physical symptoms are intricately interconnected through shared mechanisms. Systematic assessment of depressive symptoms may represent a clinically relevant target and a potential leverage point for integrated care pathways in chronic pain services.