SLC6A3 and major depressive disorder: Regarding the study’s pharmacogenetic analysis and considering five groups of most frequently used therapeutic agents (mirtazapine, selective serotonin reuptake inhibitors (SSRIs), tricyclics, venlafaxine, and others), the SLC6A3 3′UTR VNTR variant influenced more prominently the response to SSRIs, as individuals with at least one L (10R) allele responded better to the treatment decreasing their Hamilton Rating Scale for Depression (HDRS) scores (p = 0.026).