In more details to the best of our knowledge the first paper to describe a possible association between ABCB1 variants with SSRIs response was the interesting paper from Kato et al., [24] which examined the possible association of 3 functional ABCB1 polymorphisms (C3435T: rs1045642, G2677T/A: rs2032582, c1236t: RS1128503) with response to paroxetine in a Japanese major depression sample cohort. This evidence concerns the gene ABCB1 and major depressive disorder.