Study inclusion criteria
| Criterion | Description |
|---|---|
| Population | Human, aged 18 years or older |
| Intervention | Probiotic (consumption of live microorganisms) Prebiotic (compound[s] to induce growth or activity of gut microbiota) Synbiotic (combination of probiotic and prebiotic) Paraprobiotic (sterilized or inactivated bacteria) Fecal microbiota transplant |
| Comparator | Placebo or control, defined by the absence of intervention |
| Outcome | Depressive symptoms, measured with a validated tool |
| Design | Randomized controlled trials |