← All sources
Gut feeling: randomized controlled trials of probiotics for the treatment of clinical depression: Systematic review and meta-analysis
Systematic review locating only three RCTs (n=229) of probiotics in clinically depressed adults; after removing one heterogeneous standalone trial, the pooled random-effects SMD on depressive symptoms was 1.37 (95% CI 0.13–2.61), with authors stressing very limited evidence and adjunctive-treatment context.
Design
- SR + MA of RCTs in clinical depression
- Eligible: probiotics as standalone or adjunct to antidepressants
- Included: 3 RCTs (n = 229 randomized)
Pooled signal (abstract)
- After excluding one standalone trial for clinical heterogeneity, pooled SMD = 1.371 (95% CI 0.130–2.613) favouring probiotics on depressive symptom scales.
- Strain / regimen heterogeneity and very small trial count—authors conclude evidence is limited but suggestive especially with antidepressants.
Evidence hygiene
Do not equate with IBS-focused probiotic meta-analyses on ford-2018-ibs-probiotics-antibiotics-meta-aliment-pharmacol-ther—population and endpoints differ.
Publication
Nikolova V, et al. Ther Adv Psychopharmacol. 2019;9:1754320919859031. PMID 31263542.
Outcomes
- Effect Size (Cohen's d / SMD)1.371d (Cohen's d)
- Authors conclude limited RCT corpus for probiotics in diagnosed depression; adjunct-to-antidepressant context highlighted.