RESUMEN
BACKGROUND: Transcranial magnetic stimulation (TMS) is considered an effective and fast option for treating patients with major depressive disorder. With the increase in treatment options, the determination of biomarkers that predict which treatment will benefit patients the most has been a matter of curiosity for researchers. SUBJECTS AND METHODS: In this study, we aimed to determine the changes in serum concentrations of S100B, a neurotrophic factor thought to play a role in psychiatric disorders after repetitive TMS (rTMS) and anti-depressant drugs (AD) therapy in patients with major depressive disorder(MDD).In this cohort study, rTMS was applied to the left dorsolateral prefrontal cortex(DLPFC) of drug-resistant MDD patients, while another group of MDD patients was treated with AD for three weeks. Patients were evaluated by psychometric tests and serum S100B concentration at baseline and following intervention. There was also a healthy control group in which patients' S100B values were compared at baseline. RESULTS: There is a population with a total of 48 participants.(16 healthy controls,16 anti-depressant treatment groups, 16 individuals who received rTMS in addition to anti-depressant ) A total of 48 participants completed the study, and the S100B levels of the rTMS group and the anti-depressant drug group were found to be significantly higher than the healthy control group. S100B values, which were higher in the anti-depressant and rTMS groups compared to healthy controls, showed a significant reduction in group time interaction (start and end of treatment). CONCLUSION: rTMS of DLPFC demonstrated an effective complementary treatment for treatment-resistant patients with MDD, especially for patients with relatively high serum S100B concentrations.