FIGURE4| Summaryofthereverse-directionalMendelianrandomization(MR)analysisforinsomniaonmajordepression(MDD). (A) Reverse-directionalMReffect size of each instrumental variable (IV), MR-Egger, and inverse variance weighted (IVW). (B) Scatter plot of the causal effects of MDD on insomnia. We use vertical and horizontal black lines to show 95% CI of the estimated effect of IVs on MDD (x-axis) and that on insomnia (y-axis), respectively. We use the blue line to show the IVW random-effects model. The potential SNP outliers (rs3099439 and rs10913112) are highlighted in green. (C) Funnel plot of the causal effect of MDD on insomnia. Each point represents the estimated causal effect of each IV. The vertical dark blue line represents the causal effect estimate obtained using the MR-Egger method; the light blue line represents the causal effect estimate obtained using the IVW method. The potential outliers (rs3099439 and rs10913112) are highlighted in green.