Liafensine is a triple reuptake inhibitor targeting transporters for serotonin, norepinephrine, and dopamine for treatment-resistant depression (TRD). It did not exhibit efficacy in non-biomarker-selected TRD patients in two Phase 2b studies. We utilized the blood samples from the patients enrolled in these two studies and extracted genomic DNA to conduct a genome‑wide association study aiming to find a biomarker which can predict liafensine response. A single single-nucleotide polymorphism (SNP