Internalizing Psychopathology across the Life Course: From Genes and Environment to Gene-Environment Interaction

Internalizing psychopathology (i.e., depression and anxiety) is a leading cause of disability worldwide. The recognition that both genetic factors (nature) and environmental factors (nurture) contribute to the aetiology of internalizing disorders has led to a rapid growth in research of gene–environment interactions (G×E) and of epigenetic mechanisms underlying G×E. The purpose of this paper was to critically review evidence on the contributions of genes, environments and G×E to the risk of internalizing psychopathology across the life course. The existing G×E studies have primarily focused on a limited number of candidate genes. Overall, albeit with some conflicting findings, these studies have supported G×E effects on the risk for depressive and anxiety outcomes. Future G×E studies would benefit from more systematic assessment of both negative and positive environmental influences, utilization of a developmentally sensitive life-course approach, and thorough investigations of epigenetic mechanisms that can underlie the complex gene-environment co-action.