Duloxetine, a prominent member of the class of selective serotonin and norepinephrine reuptake inhibitors (SNRIs), has carved out a significant niche in clinical practice for the management of major depressive disorder (MDD) [20,21], whereas SSRIs, like Fluoxetine, Paroxetine, and Sertraline, primarily act on the reuptake of 5-HT. This evidence concerns the gene HTR5A and major depressive disorder.