Objective: Fibromyalgia syndrome (FMS) and major depressive disorder (MDD) frequently co-occur together, but the mechanisms linking these conditions remain poorly understood. This study aimed to delineate symptom clusters within the FMS-MDD network, identify bridging symptoms connecting these clusters, and evaluate the integrative role of pain severity. Methods: Cross-sectional data from 3,044 patients with FMS (94% female; mean age = 52.4, SD = 9.28) were analyzed using a mixed graphical model. From an initial pool of 238 items, 30 symptom nodes were selected through a systematic reduction process. Results: The analysis revealed seven distinct symptom clusters: Pain Severity and Functional Impact, Autonomic and Somatic Complaints, Trauma and Anxiety-driven Symptomatology, Sexual and Health Concerns, Anhedonia and Social Disconnection, Cognitive–Affective and Psychomotor Dysfunctions, and Sleep, Energy Levels, and Social Functioning. Six symptoms were identified as key bridges between clusters, with Depressed Mood (z = 2.43), Fatigue (z = 2.06), and Anxiety & Nervousness (z = 2.09) showing the highest bridge centrality. Surprisingly, Pain Severity exhibited minimal connectivity, ranking 18th in bridge strength (z =- 0.59), and primarily linked to Sleeping Problems and Fatigue. Conclusion: Our findings suggest that emotional and fatigue-related symptoms play a more central role in linking FMS and depression than Pain Severity alone. Bridge symptoms such as Fatigue and Depressed Mood may represent clinically meaningful targets for symptom-focused interventions. As this study is cross-sectional, causal inferences cannot be drawn. Longitudinal studies are needed to examine temporal dynamics and test whether targeting bridge symptoms improves clinical outcomes.
Reichert et al. (Sat,) studied this question.