Abstract
BACKGROUND/OBJECTIVES: Chronic musculoskeletal pain without a clearly identifiable medical cause is characterised by significant emotional distress and/or functional disability. Given the relatively limited research specifically addressing chronic primary musculoskeletal pain (CPMP), as defined in the latest revision of the International Classification of Diseases (ICD-11), the present study aimed to examine its psychopathological and sleep-related implications, and to explore whether pain intensity is associated with psychological distress and poor sleep quality. METHODS: This observational study included 60 adult participants, comprising 30 patients diagnosed with CPMP and 30 healthy controls without any diagnosis. Participants completed the Numeric Pain Rating Scale (NPRS), the Symptom Checklist-90-R (SCL-90-R), and the Pittsburgh Sleep Quality Index (PSQI). RESULTS: Patients with CPMP exhibited significantly higher levels of psychopathological symptomatology on the SCL-90-R and poorer sleep quality on the PSQI compared to controls (p < 0.05 for most dimensions). Greater pain intensity on the NPRS was strongly associated with psychological distress (e.g., GSI: r = 0.838, p < 0.01) and poor sleep quality (r = 0.785, p < 0.01). Hierarchical regression analyses revealed that pain intensity may play a meaningful role in both psychological distress and sleep quality (p < 0.05 across all models), even after statistically controlling for sex, age, and pain duration. CONCLUSIONS: These findings suggest that pain intensity is not only a key physical symptom, but also a relevant factor in understanding the broader psychological vulnerability in patients with CPMP. The present study contributes to a deeper understanding of the psychopathological and functional impact of CPMP and underscores the need for tailored psychological interventions to address the comorbid symptoms associated with this condition.