Mentalizing, Loneliness and Pain-Related Depressive Symptoms Are Associated with Pain Severity in Patients with Rheumatic Diseases: Results of a Cross-Sectional Secondary Analysis

<b>Background/Objectives</b>: Patients with rheumatic diseases often experience pain-related depressive symptoms, potentially exacerbated by feelings of loneliness and social isolation. This study explores the role of mentalizing, i.e., the understanding of inner mental states in oneself and others, as a protective factor in this context. <b>Methods</b>: In this secondary analysis, <i>n</i> = 76 patients completed the FESV depression scale, MZQ UCLA loneliness scale and pain severity items from the German Pain Questionnaire. Structural equation models and mediation analyses were employed to test different theoretical models. <b>Results</b>: The best model fit was found for Model 3, which described the association of loneliness with pain severity (β = 0.34, <i>p</i> = 0.004). The association was fully mediated by a sequential mediation of mentalizing and pain-related depression. Adding the mediators increased the overall explained variance of pain severity from 12% to 41% with an excellent model fit (CFI > 0.99; TLI > 0.99; RMSEA = 0.001). <b>Conclusions</b>: The study suggests that patients' pain severity may be influenced by the interaction between loneliness, depressive symptoms and mentalizing abilities. The negative impact of pain-related depressive symptoms and loneliness on pain severity underscores the need for their targeted management in routine care for chronic pain patients. Improvement of mentalizing may be a resilience factor for these patients.