Fig. 3: Funnel plots from both meta-analyses.

A Study-level funnel plot of the meta-analysis assessing depression occurrence and 5-HTT promoter methylation. B Study-level funnel plot of the meta-analysis assessing depression severity and 5-HTT promoter methylation. The dashed red line represents a regression line connecting the standard error and the effect size. The white dots indicate the combined effects at the study level. The black dots represent potential missing studies, estimated through trim-and-fill analysis.