There are currently no published studies on environmental moderation of effects associated with CHRM2, and in this first effort to examine such moderation, we found suggestions of a crossover effect in two independent samples. The possibility that CHRM2 is a plasticity gene, rather than a vulnerability gene, provides a potential explanation for the observed results involving this gene. CHRM2 may not be a gene “for” any one disorder; rather, if it is a gene involved in biological sensitivity to context, it would be expected to have effects on a range of outcomes, which is the pattern that has been observed for this gene. Further, most of the genetic studies of CHRM2 have not incorporated environmental information, and this could help account for the variability in the findings concerning possible main effects associated with CHRM2: If a sample has an average mean level on the relevant environmental dimension, then no main effect of CHRM2 would be observed, as sampling is occurring essentially where the lines cross on Figure 4b. However, deviation from mean levels on the relevant environmental dimension (in either
