Major depressive disorder is complex and heterogeneous

The risk of major depressive disorder (MDD) is determined by the combination of biological susceptibility and the risk or protective factors present in the environment.¹ The effect of risk or protective factors may be specific to a particular context or time, and any one specific risk or protective factor accounts for only a small proportion of MDD risk, as these factors are generally not specific to MDD.¹

Reference:

1. Marx W, Penninx BWJH, Solmi M, et al. Major depressive disorder. Nat Rev Dis Primers 2023; 9 (1): 44.