Multivariable analyses adjusting for potential confounders showed that participants with moderate/severe CD had significantly worse self-reported depression and anxiety than those with mild CD (PHQ-9: 9.78 [SE: 0.38] vs. 7.33 [SE: 0.23]; P < .001 and GAD-7: 6.76 [SE: 0.30] vs. 5.55 [SE: 0.21]; P = .001; Figure 2A, Supplementary Table S1). This evidence concerns the gene GAD1 and major depressive disorder.