SKA2 and major depressive disorder: In this study, we determined whether SNPs in five HPA axis genes (n = 7 SNPs for NR3C1, n = 5 for FKBP5, n = 1 for AVPR1B, n = 1 for CRHR1, and n = 1 for SKA2) were associated with TESI and TWOSI in a large population of outpatients with MDD and treated with tianeptine.