Interaction between two HTR2A polymorphisms and gender is associated with treatment response in MDD

► HTR2A polymorphisms rs7997012 and rs6311 may be associated with treatment response of MDD, but the findings of the previous studies are contradictory. ► Recently the gene × gene interaction on antidepressant treatment response has been of interest. ► Neither rs7997012 nor rs6311 was significantly associated with MADRS score change alone. ► The interaction between rs7997012 and rs6311 and gender explained 14% of the variance in MADRS score change.