The nonenzymatic antioxidant profile as a biomarker for adolescent mood disorders: Cross-sectional and longitudinal analyses

ObjectiveThis study aimed to investigate the associations between serum nonenzymatic antioxidants and major depressive disorder or bipolar disorder in adolescents.MethodsCross-sectional (410 adolescents: 178 patients with major depressive disorder, 54 patients with bipolar disorder, and 178 healthy controls) and longitudinal (72 adolescents: 55 patients with major depressive disorder and 17 patients with bipolar disorder) analyses were conducted. Antioxidant levels were measured and correlated with diagnosis and Hamilton Depression Rating Scale scores. Treatment-related changes in uric acid, albumin, and total bilirubin were assessed in the longitudinal cohort.ResultsPatients with major depressive disorder and bipolar disorder showed higher uric acid (p = 0.019) and lower albumin and total bilirubin (p < 0.001) than in controls. Multivariate regression analysis identified uric acid as a risk factor for major depressive disorder (odds ratio = 2.52, p = 0.003) and bipolar disorder (odds ratio = 4.66, p = 0.001), whereas albumin and total bilirubin were protective factors (p < 0.001). Post-treatment, uric acid decreased in patients with major depressive disorder (336.7 ± 82.5 to 314.1 ± 76.5 µmol/L, p = 0.017) and bipolar disorder (341.9 ± 106.8 to 314.5 ± 102.4 µmol/L, p = 0.013), whereas total bilirubin increased in patients with major depressive disorder (8.8 ± 3.4 to 11.0 ± 4.6 µmol/L, p = 0.001). Uric acid was correlated positively with Hamilton Depression Rating Scale scores in patients with major depressive disorder (r = 0.32, p < 0.001) and showed a trend in patients with bipolar disorder (r = 0.33, p = 0.06). Total bilirubin showed an inverse correlation with Hamilton Depression Rating Scale scores in patients with major depressive disorder (r = -0.30, p = 0.002).ConclusionAdolescent patients with major depressive disorder and bipolar disorder exhibit antioxidant imbalances. Elevated uric acid may act as a risk factor, whereas reduced albumin and total bilirubin appear protective, suggesting their role as biomarkers for disease status and treatment response.