INTERACTIONS BETWEEN GUT MICROBIOTA AND DEPRESSIVE AND ANXIETY DISORDERS: A COMPREHENSIVE REVIEW

Natalia Maria Leśniak; Klaudia Martyna Patrzykąt; Anna Maria Zakrzewska; Aleksander Midera; Julia Aleksandra Leśniak; Michał Borowski; Klaudia Elżbieta Niwińska; Julia Agnieszka Michalak; Monika Augustyn; Kinga Popielarska; Kacper Jaskulski

doi:10.31435/ijitss.1(49).2026.5025

Authors

Natalia Maria Leśniak Central Clinical Hospital of the Medical University of Łódź, Łódź, Poland https://orcid.org/0009-0006-0815-6554
Klaudia Martyna Patrzykąt 109 Military Hospital with Policlinic in Szczecin, Szczecin, Poland https://orcid.org/0009-0000-9440-5444
Anna Maria Zakrzewska Central Clinical Hospital of the Medical University of Łódź, Łódź, Poland https://orcid.org/0009-0009-8757-2274
Aleksander Midera Independent Public Healthcare Center, Brzeziny, Poland https://orcid.org/0009-0008-5809-427X
Julia Aleksandra Leśniak Central Clinical Hospital of the Medical University of Łódź, Łódź, Poland https://orcid.org/0009-0005-7375-5951
Michał Borowski Independent Public Healthcare Center, Mińsk Mazowiecki, Poland https://orcid.org/0009-0004-7316-2411
Klaudia Elżbieta Niwińska Independent Public Clinical Hospital named after Prof. W. Orłowski (CMKP), Warszawa, Poland https://orcid.org/0009-0002-3648-277X
Julia Agnieszka Michalak Independent Public Healthcare Center, Kościan, Poland https://orcid.org/0009-0006-2629-7692
Monika Augustyn Uniwersytet Medyczny im. Piastów Śląskich we Wrocławiu, Wrocław, Poland https://orcid.org/0009-0008-5554-8926
Kinga Popielarska Medical University of Gdańsk, Gdańsk, Poland https://orcid.org/0009-0009-7797-5301
Kacper Jaskulski Central Clinical Hospital of the Medical University of Łódź, Łódź, Poland https://orcid.org/0009-0006-1631-8058

DOI:

https://doi.org/10.31435/ijitss.1(49).2026.5025

Keywords:

Gut Microbiota, Intestinal Microbiome, Microbiome Composition, Gut–Brain Axis, Microbiota–Gut–Brain Axis, Depression, Major Depressive Disorder, Anxiety, Anxiety Disorders, Short-Chain Fatty Acids, Microbial Metabolites, Probiotics, Prebiotics, Psychobiotics

Abstract

Background. Depressive and anxiety disorders are major challenges in modern medicine and are increasingly linked to gut dysbiosis. Evidence indicates that affected patients often exhibit reduced microbial diversity, lower levels of SCFA-producing bacteria, and increased pro-inflammatory taxa. Proposed mechanisms include altered SCFA production, neurotransmitter modulation, vagus nerve signaling, immune activation, HPA axis dysregulation, and impaired gut and blood–brain barrier integrity

Aim. This review summarizes current evidence on the gut-brain axis and how it impacts mood disorders.

Material and methods. The review analyzed English-language studies published between 2015 and 2025 using PubMed, SpringerLink, and Elsevier, focusing primarily on human research examining the gut microbiota, gut–brain axis, and their association with depressive and anxiety disorders.

Results. The review highlights the potential of microbiota-based therapies for mood disorders. Probiotics, especially psychobiotic strains, show the most consistent benefits in reducing depressive and anxiety symptoms, while evidence for prebiotics and dietary interventions remains limited. Current studies are constrained by methodological heterogeneity, small sample sizes, and short intervention durations.

Conclusions. Overall, accumulating data support the gut microbiota as a significant contributor to the development and modulation of depressive and anxiety disorders. While definitive clinical recommendations cannot yet be made, microbiota modulation represents a promising avenue for future integrative treatment approaches and warrants further rigorous investigation.

References

Sender, R., Fuchs, S., & Milo, R. (2016). Revised estimates for the number of human and bacteria cells in the body. PLoS Biology, 14(8), e1002533. https://pmc.ncbi.nlm.nih.gov/articles/PMC4991899/

World Health Organization. (n.d.). Depression. https://www.who.int/news-room/fact-sheets/detail/depression

Simpson, C. A., Diaz-Arteche, C., Eliby, D., Schwartz, O. S., Simmons, J. G., & Cowan, C. S. M. (2020). The gut microbiota in anxiety and depression: A systematic review. Clinical Psychology Review, 83, 101943. https://pubmed.ncbi.nlm.nih.gov/33271426/

Knuesel, T., & Mohajeri, M. H. (2022). The role of the gut microbiota in the development and progression of major depressive and bipolar disorder. Nutrients, 14(10), 2081. https://pubmed.ncbi.nlm.nih.gov/35010912/

Gao, M., Wang, J., Liu, P., Tu, H., Zhang, R., Zhang, Y., Sun, N., & Zhang, K. (2023). Gut microbiota composition in depressive disorder: A systematic review, meta-analysis, and meta-regression. Translational Psychiatry, 13, Article 113. https://pubmed.ncbi.nlm.nih.gov/38065935/

Cao, Y., Cheng, Y., Pan, W., Diao, J., Sun, L., & Meng, M. (2025). Gut microbiota variations in depression and anxiety: A systematic review. BMC Psychiatry, 25, Article 6871. https://pubmed.ncbi.nlm.nih.gov/40312666/

Hu, X., Li, Y., Wu, J., Zhang, H., Huang, Y., Tan, X., Wen, L., Zhou, X., Xie, P., Olasunkanmi, O. I., Zhou, J., Sun, Z., Liu, M., Zhang, G., Yang, J., Zheng, P., & Xie, P. (2023). Changes of gut microbiota reflect the severity of major depressive disorder: A cross-sectional study. Translational Psychiatry, 13, Article 188. https://pubmed.ncbi.nlm.nih.gov/37117202/

Jiang, H.-Y., Zhang, X., Yu, Z.-H., Zhang, Z., Deng, M., Zhao, J.-H., & Ruan, B. (2018). Altered gut microbiota profile in patients with generalized anxiety disorder. Journal of Psychiatric Research, 104, 130–136. https://pubmed.ncbi.nlm.nih.gov/30029052/

Cheng, J., Hu, H., Ju, Y., Liu, J., Wang, M., Liu, B., & Zhang, Y. (2024). Gut microbiota-derived short-chain fatty acids and depression: Deep insight into biological mechanisms and potential applications. General Psychiatry, 37(1), e101374. https://pubmed.ncbi.nlm.nih.gov/38390241/

Chen, M., Lyu, Q., Huang, L., Lou, Y., & Wang, L. (2024). Gut-brain axis and depression: Focus on amino acid and short-chain fatty acid metabolism. Frontiers in Behavioral Neuroscience. https://pubmed.ncbi.nlm.nih.gov/40905348/

Wang, I.-C., Buffington, S. A., & Salas, R. (2024). Microbiota-gut-brain axis in psychiatry: Focus on depressive disorders. Current Psychiatry Reports, 26, Article 349. https://pubmed.ncbi.nlm.nih.gov/40130013/

Zhou, X., Wang, S., Wang, X., Chen, X., Zhou, P., Ma, K., & Zhang, P. (2025). Mechanisms of the effect of gut microbes on depression through the microbiota–gut–brain axis. Frontiers in Nutrition, 12, 1634548. https://pubmed.ncbi.nlm.nih.gov/40843192/

Zhu, F., Tu, H., & Chen, T. (2022). The microbiota-gut-brain axis in depression: Potential pathophysiological mechanisms and microbiota combined antidepression effect. Nutrients, 14(10), 2081. https://pubmed.ncbi.nlm.nih.gov/35631224/

Freimer, D., Yang, T. T., Ho, T. C., Tymofiyeva, O., & Leung, C. (2022). The gut microbiota, HPA axis, and brain in adolescent-onset depression: Probiotics as a novel treatment. Brain, Behavior, & Immunity - Health, 24, 100541. https://pubmed.ncbi.nlm.nih.gov/36536630/

Toader, C., Dobrin, N., Costea, D., Glavan, L.-A., Covache-Busuioc, R.-A., Dumitrascu, D.-I., Bratu, B.-G., Costin, H.-P., & Ciurea, A. V. (2023). Mind, mood and microbiota—Gut–brain axis in psychiatric disorders. Journal of Clinical Medicine, 12, Article 2139. https://pubmed.ncbi.nlm.nih.gov/38542314/

Liu, R. T., Walsh, R. F. L., & Sheehan, A. E. (2019). Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials. Neuroscience & Biobehavioral Reviews, 102, 13–23. https://pubmed.ncbi.nlm.nih.gov/31004628/

Asad, A., Kirk, M., Zhu, S., Dong, X., & Gao, M. (2024). Effects of prebiotics and probiotics on symptoms of depression and anxiety in clinically diagnosed samples: Systematic review and meta-analysis of randomized controlled trials. Nutrition Reviews. Advance online publication. https://pubmed.ncbi.nlm.nih.gov/39731509/

Rahmannia, M., Poudineh, M., Mirzaei, R., Aalipour, M. A., Bonjar, A. H. S., Goudarzi, M., Kheradmand, A., Aslani, H. R., Sadeghian, M., Nasiri, M. J., & Sechi, L. A. (2024). Strain-specific effects of probiotics on depression and anxiety: A meta-analysis. Gut Pathogens, 16, Article 34. https://pubmed.ncbi.nlm.nih.gov/39245752/

Śliwka, A., Polak-Berecka, M., Zdybel, K., Zelek-Molik, A., & Waśko, A. (2023). Psychobiotics in depression: Sources, metabolites, and treatment—A systematic review. Nutrients, 17(13), 2139. https://pubmed.ncbi.nlm.nih.gov/40647242/

Meyyappan, A. C., Forth, E., Wallace, C. J. K., & Milev, R. (2020). Effect of fecal microbiota transplant on symptoms of psychiatric disorders: A systematic review. BMC Psychiatry, 20, 299. https://pubmed.ncbi.nlm.nih.gov/32539741/

Liu, R. T., Walsh, R. F. L., & Sheehan, A. E. (2019). Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials. Neuroscience & Biobehavioral Reviews, 102, 13–23. https://pubmed.ncbi.nlm.nih.gov/31004628/

El Dib, R., Periyasamy, A. G., de Barros, J. L., França, C. G., Senefonte, F. L., Vesentini, G., Alves, M. G. O., Rodrigues, J. V. da S., Gomaa, H., Gomes Júnior, J. R., Costa, L. F., Von Ancken, T. de S., Toneli, C., Suzumura, E. A., Kawakami, C. P., Faustino, E. G., Jorge, E. C., Almeida, J. D., & Kapoor, A. (2021). Probiotics for the treatment of depression and anxiety: A systematic review and meta-analysis of randomized controlled trials. Clinical Nutrition ESPEN, 45, 93–102. https://pubmed.ncbi.nlm.nih.gov/34620373/

Butler, M. I., Mörkl, S., Sandhu, K. V., Cryan, J. F., & Dinan, T. G. (2019). The gut microbiome and mental health: What should we tell our patients? The Canadian Journal of Psychiatry, 64(11), 747–752. https://pubmed.ncbi.nlm.nih.gov/31530002/