Table 1:

Study inclusion criteria

PopulationHuman, aged 18 years or older
InterventionProbiotic (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
ComparatorPlacebo or control, defined by the absence of intervention
OutcomeDepressive symptoms, measured with a validated tool
DesignRandomized controlled trials