Major depressive disorder (MDD) is a common and debilitating disorder with pervasive impact on the quality of life for both sufferers and their families. Lifetime prevalence is estimated to be ∼15%,1, 2 and is consistently estimated to be twice as common in women as men.3, 4 MDD is associated with high morbidity, reflected in estimates of burden of disease and years lost in productivity,1, 5 and excess mortality from suicide6 and other causes. Our understanding of the etiology of MDD remains fragmented, despite wide-ranging research, but is the key to effective prevention and treatment.
