Comparison of Clinical Indicators for Differentiating Unipolar and Bipolar Depression

Background The global prevalence of major depressive disorder and bipolar depression (BD) has increased, with BD often underdiagnosed and mismanaged. This study aims to identify key biomarkers from demographic and laboratory indicators to differentiate unipolar depression (UD) from BD, aiding early diagnosis and personalized treatment. Methods This study was conducted at the Second Affiliated Hospital of Xinxiang Medical University between January 2022 and December 2024. A total of 174 inpatients were included, with 87 diagnosed with UD and 87 with BD. Demographic and laboratory data were collected. Univariate and multivariate logistic regression analyses were conducted to identify the risk factors. Receiver operating characteristic (ROC) curve analysis was used to evaluate discriminatory ability. Results BD exhibited a higher male proportion ( p = 0.004) and significantly elevated total bilirubin (TBIL), creatinine, and creatine kinase (CK) levels, along with lower thyroxine (T4) levels, compared to UD ( p < 0.05). Multivariate analysis identified platelets, TBIL, T4, and CK as independent risk factors ( p < 0.05). ROC analysis revealed TBIL (Area Under the Curve [AUC] = 0.609) and CK (AUC = 0.621) as key discriminators, with a combined model achieving an AUC of 0.724, sensitivity of 75.9%, and specificity of 59.8%. Conclusions Key metabolic and muscular biomarkers, including TBIL, CK, PLT, and T4, were identified as potential differentiators between UD and BD. These findings demonstrated diagnostic potential and underscored the need for further validation in larger studies.