¹The First Hospital of Hebei Medical University, Mental Health Center, Shijiazhuang, China

Background: Unipolar depression disorder (UDD) and bipolar depression disorder (BDD) present with highly overlapping clinical manifestations. The lack of objective biomarkers has long posed a challenge in the clinical diagnosis of these disorders.Numerous studies have verified the potential diagnostic value of the niacin skin flushing response (NSFR) in a wide range of psychiatric diseases. Its primary mechanism is closely associated with phospholipid metabolism. In this study, we intended to compare blood lipid levels and the performance of NSFR in in patients with UDD and BDD. Moreover, we aimed to determine its clinical potential as an auxiliary diagnostic biomarker for differentiating between these two disorders.

Aims & Objectives: NSFR and blood lipids were measured in 30 BDD patients, 87 UDD patients, and 67 healthy controls. All participants underwent NSFR assessment and blood lipid measurement. A logistic regression-based diagnostic model for UDD/BDD discrimination was established using NSFR and lipid indices.

Method: BDD exhibited a more blunted outcome in NSFR compared to UDD (p = 0.001), and it also had higher triglyceride levels (p = 0.021). Moreover, the research findings revealed that a correlation between blood lipids and NSFR was observed only in cases of bipolar depressive disorder. NSFR index had an AUC of 0.719 in distinguishing UDD from BDD, which increased to 0.857 when combined with triglyceride and age at onset.

Results: BDD exhibited a more blunted outcome in NSFR compared to UDD (p = 0.001), and it also had higher triglyceride levels (p = 0.021). Moreover, the research findings revealed that a correlation between blood lipids and NSFR was observed only in cases of bipolar depressive disorder. NSFR index had an AUC of 0.719 in distinguishing UDD from BDD, which increased to 0.857 when combined with triglyceride and age at onset.

Discussion & Conclusions: Integrated blunted NSFR and blood lipids hold promise as potential biomarkers for UDD/BDD discrimination. This study provides a novel strategy for early BDD detection and new insights into BDD diagnosis and management.