Evaluation of Thiol/Disulfide Interrelation in Major Depressive Disorder.

Objective: Although major depressive disorder (MDD) constitutes a significant part of mental health problems, its pathogenesis has not been fully elucidated. The inadequacy of diagnostic tests specific to MDD causes difficulty in diagnosis. Therefore, we investigated the situation of thiol/disulfide imbalance, which may play a role in the pathogenesis of many diseases, in MDD patients.

Methods: Forty-five MDD patients and 40 non-patient volunteers participated in our study. Sociodemographic data form, Beck Depression Scale, and Clinical Global Impression Scale were used in making the diagnosis and evaluation process.

Results: There was a significant difference between the MDD and non-patient groups in native thiol and total thiol levels, disulfide/native thiol, disulfide/total thiol, and native thiol/total thiol ratios. No significant difference was detected in terms of disulfide level between the 2 groups. There was no significant difference between the patients' thiol disulfide ratios and the severity of depression. There was no significant difference between the patients' symptom duration and thiol disulfide ratios. Nevertheless, a negative correlation was identified between the duration of the patients' symptoms and their disulfide levels.

Conclusion: When the results were examined in terms of thiol and disulfide ratios, they showed that thiol and disulfide ratios were impaired in depression. We think that thiol/disulfide parameters may be a biomarker candidate that can help in the diagnosis of MDD.