Plasma levels of quinolinic acid and kynurenic acid in patients with major mental illnesses

Authors

DOI:

https://doi.org/10.11603/ijmmr.2413-6077.2026.1.16439

Keywords:

antipsychotics, inflammation, tryptophan metabolism, mental health disorders, neuroprotection

Abstract

Abstract. Clarifying antipsychotic effects on kynurenine-pathway metabolites may improve understanding of their role in major mental illnesses. Therefore, this study aimed to assess plasma quinolinic and kynurenic acid levels in patients with major mental illnesses. 85 adults comprising 55 treatment-experienced patients with major mental illnesses; schizophrenia, bipolar and depression, and 30 controls were enrolled into this study. The plasma levels of quinolinic acid and kynurenic acid were determined using Enzyme Linked Immunosorbent Assay. Plasma quinolinic acid level was significantly lower in patients with major mental illnesses (14.52 (7.16-48.24) mg/mL) compared with the controls (157.79 (68.64-464.05) mg/mL). In contrast, plasma kynurenic acid level was higher in patients with major mental illnesses  (243.96  (210.65-283.05)  μmol/L)  compared  with  the  controls  (215.36  (185.67-243.65)  μmol/L).  After

stratification into groups, patients with schizophrenia (22.86 (7.62-53.14) mg/mL), bipolar (15.34 (8.37-48.21) mg/mL) and depression (6.18 (2.66-43.05) mg/mL) had significantly lower quinolinic acid levels compared with the controls (157.79 (68.64-464.05) mg/mL). However, kynurenic acid levels were only significantly elevated in patients with schizophrenia (247.0 (208.34-290.22 μmol/L) and bipolar (243.20 (212.85-291.12) μmol/L) compared with the controls (215.36 (185.67-243.65) μmol/L). The plasma levels of quinolinic acid and kynurenic acid did not differ significantly among patients with schizophrenia, bipolar disorder, and depression. Treated patients with major mental illnesses exhibited a kynurenine metabolite profile indicative of reduced neurotoxicity and enhanced neuroprotection. These metabolites may serve as potential biomarkers for monitoring treatment effects

Received: 27.12.2025 | Revised: 16.04.2026 | Accepted: 26.05.2026

Author Biographies

  • Sheu Rahamon, College of Medicine, University of Ibadan

    PhD, Lecturer 200285, Queen Elizabeth II Rd., Agodi, Ibadan, Nigeria 

  • Sofiyat Bello, College of Medicine, University of Ibadan

    Master, Postgraduate Student 200285, Queen Elizabeth II Rd., Agodi, Ibadan, Nigeria 

  • Abdulrahamon Sikirullah, College of Medicine, University of Ibadan

    Master, Postgraduate Student 200285, Queen Elizabeth II Rd., Agodi, Ibadan, Nigeria

  • Oluremi Oladele, College of Medicine, University of Ibadan

    Bachelor, Lecturer, Consultant Psychiatrist 200285, Queen Elizabeth II Rd., Agodi, Ibadan, Nigeria

  • Victor Lasebikan, Medicine, University of Ibadan

    PhD, Professor, Consultant Psychiatrist College 200285, Queen Elizabeth II Rd., Agodi, Ibadan, Nigeria 

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Published

2026-05-29

Issue

Vol. 12 No. 1 (2026): International Journal of Medicine and Medical Research

Section

Editorial

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Copyright (c) 2026 Sheu Rahamon, Sofiyat Bello, Abdulrahamon Sikirullah, Oluremi Oladele, Victor Lasebikan

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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

How to Cite

Plasma levels of quinolinic acid and kynurenic acid in patients with major mental illnesses. (2026). International Journal of Medicine and Medical Research, 12(1), 6-13. https://doi.org/10.11603/ijmmr.2413-6077.2026.1.16439