In some sense, figuring out to what extent something is “genetic” and/or “environmental” is a moot point. What we are ultimately interested in is the unfolding of developmental trajectories that lead to outcomes of interest. If, for example, an individual is genetically predisposed toward sensation seeking, and this makes that individual more likely to spend time in bars (a GxE correlation), and this increases their risk for alcohol problems, are the predisposing “sensation-seeking” genes or the “bar environment” the causal agent? In actuality, the question is moot: they both played a role; it is much more informative to try to understand the pathways of risk than to ask whether genes or the environment were the critical factor. Although this review focuses on GxE interaction, it is important for the reader to be aware that this is but one process by which genetic and environmental influences are intertwined. Excellent reviews covering the nature and importance of GxE correlation also exist (Kendler, 2010).
