Aim: The purpose of the present study was to investigate whether total antioxidant capacity (TAC) and total oxidant status (TOS) are associated with major depressive disorder (MDD) and to evaluate the impact of antidepressant treatment on TAC and TOS in MDD.
Methods: Fifty-seven MDD patients and 40 healthy controls participated in the study. Serum TAC and TOS were measured both in patients and controls using Erel's methods. Patients were treated with antidepressant drugs for 12 weeks. The treatment course was evaluated using the Montgomery–Asberg Depression Rating Scale (MADRS) in all patients.
Results: TOS and oxidative stress index (OSI) were higher (P = 0.0001 for both) and TAC was lower (P = 0.0001) in the MDD group compared with those of the controls. After 3 months of antidepressant treatment, TOS and OSI were decreased and TAC was increased compared with the pretreatment values (P = 0.0001, for all). Furthermore, there were significant positive correlations between the severity of the disease and serum TOS and OSI (r = 0.584, P = 0.0001; r = 0.636, P = 0.0001, respectively). A negative correlation was found between the severity of the disease and serum TAC (r = −0.553, P = 0.0001) at the pre-treatment stage.
Conclusion: Treatment administered for 3 months to MDD patients increases TAC while decreasing TOS and OSI.