Thiol/Disulfide Homeostasis: A Potential New Peripheral Biomarker in Adolescent Depression

Thiol-disulfide homeostasis (TDH), one of the most important antioxidants, is involved in the non-enzymatic removal of reactive oxygen molecules in the body and is one of the many methods to measure the level of oxidative stress (OS). In the present study, TDH is investigated in adolescent depression, and its relationship to clinical variables is examined.

Thirty-two (50.0%) patients diagnosed with major depressive disorder (MDD) and without psychotropic drug use and 32 (50.0%) healthy controls were included in the present study. The subjects MDD and control groups were between 13 and 18 years old. Participants completed the DSM-5 Level-2 scales for depression and irritability. A colorimetric method proposed by Erel and Neselioglu was used to analyze the TDH parameters of serum samples.

Biochemical analyses of samples from the MDD and control groups showed significant differences between the groups in native thiol (SH) levels (P = .002), disulfide (SS) levels (P = .021), disulfide/total thiol (SS/ToSH) (P = .009), and disulfide/native thiol (SS/SH) (P = .003) levels. Analysis of receiver operating characteristic showed that the area under the curve values with "acceptable discrimination potential" for the TDH parameters were significantly able to discriminate individuals with MDD from healthy controls.

Thiol-disulfide homeostasis, one of the OS parameters, was found to be impaired in adolescents with depression. Our results suggest that TDH may contribute to the etiopathogenesis of adolescent MDD and that TDH may be a novel approach to assess OS in adolescent depression.