A systematic review of the effects of probiotics on depression and anxiety: an alternative therapy?

source extracted confidence: high 2026-04-09
#anxiety #anxiety-disorders #complementary-therapies #depression #humans

A systematic review of the effects of probiotics on depression and anxiety: an alternative therapy?

Minayo et al., 2021 | Cien Saude Colet | Systematic Review

Citation

Minayo Miryam de Souza, Miranda Iasmim, Telhado Raquel Senna. A systematic review of the effects of probiotics on depression and anxiety: an alternative therapy?. Cien Saude Colet. 2021-Sep;26(9):4087-4099. doi:10.1590/1413-81232021269.21342020

Abstract

This review aims to understand and analyse the effects of probiotics on depression, anxiety and psychological stress. These disorders are among the leading causes of disability worldwide. Conventional pharmacotherapies usually have a poor response or adverse side effects. In this context, recent studies have demonstrated a dense bi-directional communication named gut-brain axis. Evidences are demonstrating the relationship between disturbance in the enteric microbiome and psychiatric disorders, paving the way for the emergence of alternative therapies. A systematic search for randomized double/triple blind placebo-controlled clinical trials was performed in PubMed, Scopus and Lilacs. The studies selection followed the recommendations of the main items for report systematic reviews and meta-analyses (PRISMA). Nine articles met the criteria and were analysed for effects on depression, anxiety, psychological stress and biomarkers. Seven found positive results in at least one of the items. We concluded that the use of probiotics to alleviate depressive symptoms and anxiety is promising, mainly due to its potential anti-inflammatory effect, but additional and more rigorous double blind randomized clinical trials are necessary to endorse such conclusions.

Key Findings

We concluded that the use of probiotics to alleviate depressive symptoms and anxiety is promising, mainly due to its potential anti-inflammatory effect, but additional and more rigorous double blind randomized clinical trials are necessary to endorse such conclusions.

Outcomes Measured

  • anxiety
  • depression
  • inflammatory markers

Population

Field Value
Population See abstract
Sample Size See abstract
Age Range See abstract
Condition anxiety

MeSH Terms

  • Anxiety
  • Anxiety Disorders
  • Complementary Therapies
  • Depression
  • Humans
  • Probiotics
  • Randomized Controlled Trials as Topic

Evidence Classification

  • Level: Systematic Review
  • Publication Types: Journal Article, Systematic Review
  • Vertical: probiotics-mood

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09