Impact of painful physical symptoms on first-episode major depressive disorder in adults with subthreshold depressive symptoms: A prospective cohort study

Objective: To investigate the impact of baseline painful physical symptoms (PPS) on subsequent first-episode major depressive disorder (MDD) in adults with subthreshold depressive symptoms, including subgroup analyses to assess whether the associations differ in individuals with and without physical diseases.Methods: A total of 2343 adults with subthreshold depressive symptoms were recruited at 34 primary health care centers. PPS were measured at baseline. First-episode MDD during follow-up was diagnosed by professional psychiatrists using the Mini-International Neuropsychiatric Interview.Results: Baseline PPS showed independent impacts on first-episode MDD in adults with subthreshold depressive symptoms without physical diseases, but not in those with physical diseases. A non-linear association (P < 0.001) was observed between PPS burden and the risk of first-episode MDD. The HRs for first-episode MDD exhibited a rapidly increasing trend between PPS burden scores of 10-16, and maintained consistently high when scores exceeded 16. The analyses for specific PPS revealed that headache, neck pain, and heart or chest pain were independently associated with first-episode MDD in participants without physical diseases, the HRs were 1.57 (1.15-2.36), 1.53 (1.02-2.30), and 1.69 (1.14-2.50), respectively. Further network analysis demonstrated that heart or chest pain serves as a bridge symptom among the seven specific PPS and first-episode MDD in those without physical diseases.Conclusion: PPS burden and heart or chest pain may be significant indicators for first-episode MDD in adults with subthreshold depressive symptoms without physical diseases. Future studies should investigate whether interventions targeting PPS can prevent episode MDD in this subthreshold population.