We offer here several directions for future work. Addressing the first challenge regarding causal models in epigenetic studies will fall on the shoulders of individual investigators—we would do well to fully articulate causal models that formalize our hypotheses and guide our study designs and analytic plans prior to initiating studies. Furthermore, studies that consider only epigenetic phenomena in relation to outcomes may not be sufficient. In order to truly test our hypotheses about the role of epigenetic phenomena in explaining the mechanisms by which environmental exposures and social experiences shape psychiatric disease risk, our studies will have to include data about those very factors that may operate as antecedent exposures to epigenetic modification or as confounders of the relationship between epigenetic modification and outcomes.
