Nature and Nurture: Genetic Influences and Gene-Environment Interactions in Depression

There is a vast literature on the genetic basis for Major Depressive Disorder, a topic which only continues to expand. Several genes have been examined in the context of MDD. Some of these genetic studies have been replicated but most have not. One possible rationale for this lack of replication is an increasing recognition that gene-environment interactions play a crucial role in determining the risk of developing MDD. In this review, we highlight the findings from a Genome Wide Association study as well as linkage studies of depression and discuss the implications of these results. We then summarize some of the most important genetic variations identified in depression, including conclusions from published meta-analyses, with an emphasis on gene-environment interactions. Finally we discuss both the need for and complexity of conducting gene-environment studies in MDD, as well as limitations inherent in current approaches.