A deeper understanding of the etiology of depression, including both its genetic and environmental determinants, as well as their interplay (e.g., gene-environment interaction; GxE) will have implications for preventing depression and informing its clinical treatment. There are now numerous established environmental risk factors for depression, including poverty,13,14 negative family relationships and parental divorce,15,16 child maltreatment,17,18 and other stressful life events more generally.19,20 While the risk of depression is elevated in the immediate aftermath of experiencing these environmental adversities, the effects of adversity can persist over the lifecourse.21,22
