The changes in kynurenine metabolites induced by rTMS in treatment-resistant depression: A pilot study

Hiroshi Tateishi, Daiki Setoyama, Dongchon Kang, Jun Matsushima, Ryohei Kojima, Yuka Fujii, Seiji Mawatari, Jun Kikuchi, Yuta Sakemura, Junko Fukuchi, Takumi Shiraishi, Toshihiko Maekawa, Takahiro A. Kato, Toyoko Asami, Yoshito Mizoguchi, Akira Monji

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Background: Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation technique that is considered a valuable and promising technique for improving depressive symptoms in treatment-resistant depression (TRD). However, the exact mechanism by which rTMS ameliorates depressive symptoms remains to be clarified. Objective: The aim of the present study was to analyzed the changes in metabolites of patients with TRD in the rTMS treatment, especially focusing on the kynurenine (KYN) pathway. Methods: Thirteen participants with TRD were enrolled in a high-frequency (10 Hz) rTMS study. Cognitive function, depressive symptoms and the concentration of plasma tryptophan (TRP) metabolites were measured at baseline and at the endpoint of rTMS treatment. Results: rTMS treatment significantly improved depressive symptom scores and some subscales of cognitive dysfunction. The present study has demonstrated that rTMS treatment significantly increased plasma TRP levels and significantly decreased plasma serotonin levels, while plasma KYN and kynurenic acid level as well as KYN/TRP ratio remained unchanged. Conclusions: This is the first metabolomic study of patients with TRD undergoing rTMS treatment. To validate the present results, it is necessary to increase the number of cases including controls, use a sample of cerebrospinal fluid, and measure blood concentration over time in the course of rTMS treatment.

Original languageEnglish
Pages (from-to)194-199
Number of pages6
JournalJournal of Psychiatric Research
Publication statusPublished - Jun 2021

All Science Journal Classification (ASJC) codes

  • Psychiatry and Mental health
  • Biological Psychiatry


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