Thiol-disulphide Homeostasis in Patients with Schizophrenia: The Potential Biomarkers of Oxidative Stress in Acute Exacerbation of Schizophrenia
Şükrü Alperen Korkmaz1, Semra Ulusoy Kaymak2, Salim Neşelioğlu3, Özcan Erel3
1Department of Psychiatry, Faculty of Medicine, Çanakkale Onsekiz Mart University, Çanakkale, Turkey
2Department of Psychiatry, Gülhane Education and Research Hospital, University of Health Science, Ankara, Turkey
3Department of Biochemistry, Faculty of Medicine, Ankara Yıldırım Beyazıt University, Ankara, Turkey
Correspondence to: Şükrü Alperen Korkmaz
Department of Psychiatry, Health Practice and Research Hospital, Faculty of Medicine, Çanakkale Onsekiz Mart University, Barbaros distinct, 17000, Çanakkale, Turkey
Received: April 8, 2023; Revised: June 22, 2023; Accepted: July 2, 2023; Published online: August 2, 2023.
© The Korean College of Neuropsychopharmacology. All rights reserved.

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Objective: Recent evidence suggests that oxidative stress contributes to the pathophysiology of schizophrenia. This study aimed to compare thiol-disulphide homeostasis in acute and stable phases of schizophrenia for the first time.
Methods: Among the patients with schizophrenia, 61 in the acute-phase and 61 in the stable phase of their illness were enrolled in the study. Native thiol (NT), total thiol (TT), disulphide (SS), disulphide/native thiol, disulphide/total thiol, and native thiol/total thiol for thiol-disulphide homeostasis were compared between the groups. The Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Positive/Negative Symptoms (SAPS/SANS), Clinical Global Impression- Severity Scale (CGI-S), Barnes Akathisia Rating Scale, and Simpson-Angus Scale were used to assess symptoms.
Results: After controlling for age, sex, body mass index, and smoking status there were significant differences in NT, TT, SS/NT, SS/TT, and NT/TT, but not SS. Thiol/disulphide homeostasis has shifted in favour of the oxidative side in patients with acute-phase compared to that in stable schizophrenia. BPRS, SAPS, and CGI-S scores were significantly correlated with all six thiol-disulphide parameters, but not SANS, when controlling for age and sex. Significant receiver operating characteristic (ROC) curves were obtained for all thiol-disulphide homeostasis parameters. Discriminant analysis was found to be statistically significant in discriminating between groups.
Conclusion: These results show that oxidative status increases thiol-disulphide homeostasis in patients with acute-phase schizophrenia compared to those with stable schizophrenia. These findings suggest that thiol-disulphide parameters can be used as biomarkers for the acute exacerbation of schizophrenia.
Keywords: Schizophrenia; Biomarkers; Inflammation; Thiol; Disulfide; Oxidative stress

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