CACNA1D and major depressive disorder: Our meta-analysis results confirmed that there was no causal relationship between genetically proxied inhibition of CACNA1D and the risk of depression because the pooled confidence intervals crossed the null line (common effect model: OR = 1.01, 95% CI: 1.00-1.03; random effect model: OR = 1.09, 95% CI: 0.94-1.27).