Evidence level for pharmacogenetic testing in antidepressant treatment: a systematic review

Preemptive pharmacogenetic (PGx) testing offers a promising approach to personalized antidepressant treatment by identifying genetic variations influencing drug metabolism. By focusing on CYP2D6 and CYP2C19 genes, this strategy aims to improve treatment response, minimize adverse effects, and optimize dosing in patients with depression. This systematic review evaluates the effectiveness of preemptive PGx testing, primarily for CYP2D6 and CYP2C19, in enhancing antidepressant treatment outcomes. A comprehensive search of databases, including PubMed and Embase, was conducted to identify relevant studies. The review included randomized controlled trials and meta-analyses that assessed PGx testing in relation to treatment response and remission. Data on clinical outcomes were extracted and analyzed. PGx testing led to improved antidepressant response rates and remission at 8- and 12-week follow-ups compared to treatment-as-usual (TAU). However, where data were available, benefits were less pronounced after six months of follow-up. The findings suggest that PGx testing plays an important role in achieving earlier remission, while TAU requires a longer time to achieve remission. Preemptive pharmacogenetic testing for CYP2D6 and CYP2C19 could enhance early antidepressant treatment outcomes, offering a valuable tool for personalized medicine. Further research is required to explore implementation challenges in diverse clinical settings.