as a statistical interaction in an ANOVA, and indicates whether particular experiences, exposures, or other conditions may (on average) ameliorate or exacerbate specific genetic effects in groups of individuals with similar genetic and environmental risks. In comparison, the moderated effects approach does not address mean levels of risk, but instead evaluates whether variance in genes or environment differs across various measured conditions. Moderation can occur in either raw variances (VA, VC, and VE) or in relative effects (i.e., h2, c2, and e2), and may not necessarily coincide with G × E interactions found in mean levels. The latter point is important when evaluating G × E interactions across studies using these different approaches, since different patterns can emerge from them. For example, it is possible that certain adverse environments (e.g., low socioeconomic status (SES)) may lead to some genes exerting stronger effects (mean levels), while overall, the relative variance explained by genes (heritability) may be greater in other environments (e.g., high SES). The approach used for testing G × E interactions can vary across study design, such that adoption designs or studies with measured genes are generally required for the mean levels approach, while the moderated variance components approach may
