Potential clinical benefits of probiotics, prebiotics, synbiotics, and postbiotics for depression via the microbiota-gut-brain axis

Figure 1 Flowchart of study selection process.

Figure 2 Forest plot of the pooled effect of probiotics, prebiotics, synbiotics, and postbiotics on depression symptoms. A: Overall effect of probiotics, prebiotics, synbiotics, and postbiotics (PPSP); B: Effect of PPSP based on Hamilton Depression Rating Scale; C: Effect of PPSP based on Beck Depression Inventory. PPSP: Probiotics, prebiotics, synbiotics, and postbiotics.

Figure 3 Forest plot of sub-analysis of different gut microbiota-targeting interventions.

Figure 4 Risk of bias for included studies.

Figure 5 Funnel plot for publication bias. A: Overall effect of probiotics, prebiotics, synbiotics, and postbiotics (PPSP); B: Effect of PPSP based on Hamilton Depression Rating Scale; C: Effect of PPSP based on Beck Depression Inventory.