Electroconvulsive therapy in the manic phase of bipolar disorder: examining oxidative stress and effects of thiol-disulfide homeostasis

Objective Given evidence for oxidative dysregulation in bipolar disorder, we examined thiol–disulphide balance (TDB) as a redox biomarker and evaluated the impact of electroconvulsive therapy (ECT) on TDB to clarify redox contributions to BD pathophysiology.Methods This observational mixed design study comprising cross-sectional case–control comparisons of BD-ECT(n = 31), BD-non-ECT (n = 46), healthy control (n = 42) groups and within-subject repeated-measures assessments across phases (mania, post-ECT where applicable, remission) in bipolar disorder, quantifying native thiol, disulphide, and total thiol to derive TDB ratios, with FDR-adjusted statistics.Results Compared with healthy controls, native thiol was lower in both manic and remission phases (e.g., Mania(299.4 ± 81.16) vs. HC(379.91 ± 48.93); p < 0.001), while disulphide was higher (e.g., Remission(22.85 ± 5.07) vs. HC(17.66 ± 4.96); p < 0.001). Within the ECT group, no significant within-patient changes in TDB indices were observed across time points (all p > 0.05).Conclusion We observed a shift of thiol–disulphide balance (TDB) towards oxidative predominance in both manic and remission phases of BD with no significant ECT-related modulation of TDB during mania. These findings highlight the need for a comprehensive examination of the impact of oxidative stress on the underlying mechanisms of BD and potential therapeutic mechanisms of ECT.