EXOG and depressive symptom measurement: Precisely, genotype G/G and allele G of both EXOG c.-188T > G (rs9838614) and c.*627G > A (rs1065800), and genotype C/C and allele C of ENDOG c.-220C > T (rs2997922) decreased, while allele T of EXOG c.-188T > G (rs9838614), genotype G/A and allele A of c.*627G > A (rs1065800), genotype T/T of ENDOG c.-394T > C (rs2977998) and genotype C/C and allele C of ENDOG c.-220C > T (rs2997922) increased the odds ratio of depression occurrence.