The effect of probiotics on depressive symptoms: A meta-analysis of randomized controlled trails




Probiotics; Depression; Mood disorders; Gastrointestinal microbiome.


Increasing evidence indicates bidirectional communication occurs between the gut and the brain via the microbiome-gut-brain axis. Accordingly, several studies point to a positive effect of probiotics on depressive symptomatology. Our study aimed to provide an updated meta-analysis on the subject. We conducted a systematic search for randomized clinical trials in multiple databases. Data analysis was performed using the Review Manager 5.4. We reviewed 26 studies, totaling 2,170 participants. The use of probiotics had a significant effect in reducing depressive symptoms (SMD: - 0.22; 95% CI: - 0.30 to - 0.13; p < 0.0001) compared to placebo. Subgroup analyses showed that probiotics influenced outcomes in participants with depression (SMD: - 0.67; 95% CI: - 0.93 to - 0.41; p < 0.00001) and with other clinical diagnoses (SMD: - 0.23; 95% CI: - 0.36 to - 0.09; p = 0.0008) but not healthy participants (SMD: - 0.11; 95% CI: - 0.23 to 0.02; p = 0.100). The use of probiotics can be a promising approach in improving the treatment of depression. It is important to conduct further studies to better assess the efficacy of probiotic as an adjuvant treatment to antidepressant medications, as well as their most effective dosages.

Author Biographies

Vitor Palmares Oliveira e Silva, Federal University of Pernambuco

Medical Student

Carlos Roberto Weber Sobrinho, Federal University of Pernambuco

Professor with Doctoral degree of the Tropical Medicine Department's of Federal University of Pernambuco

Rodrigo Coelho Marques, Federal University of Pernambuco

Doctoral Student in Neuropsychiatry and Behavioral sciences

Flávio Cardoso de Souza Júnior, Instituto de Medicina Integral Professor Fernando Figueira

Medical Residency in Gynecology and Obstetrics

Marcílio Lins Aroucha, Federal University of Pernambuco

Professor with Doctoral degree of the Medical Science Department of the Federal University of Pernambuco


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How to Cite

SILVA, V. P. O. e .; SILVA, M. P. O. e .; SOBRINHO, C. R. W. .; MARQUES, R. C. .; SOUZA JÚNIOR, F. C. de .; AROUCHA, M. L. . The effect of probiotics on depressive symptoms: A meta-analysis of randomized controlled trails. Research, Society and Development, [S. l.], v. 10, n. 9, p. e54510918359, 2021. DOI: 10.33448/rsd-v10i9.18359. Disponível em: Acesso em: 23 sep. 2021.



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