The origins of major depressive disorder (MDD) are complex, involving both environmental influences and a substantial genetic contribution. Genetic polymorphisms have been implicated in modulating sus Show more
The origins of major depressive disorder (MDD) are complex, involving both environmental influences and a substantial genetic contribution. Genetic polymorphisms have been implicated in modulating susceptibility, disease course, and treatment response, yet findings are often modest, population-dependent, and sometimes inconsistent. This narrative review synthesizes current evidence on genetic variants associated with MDD, highlighting well-replicated results while distinguishing exploratory or emerging findings. Key systems reviewed include serotonergic ( Show less