To test for a moderating effect of PPD on the variance components of DV (GxM), a moderation term is included on all pathways that contribute to the variance of DV (both those shared with PPD and those specific to DV). By including these moderation terms, each path can be expressed both in terms of a main effect of that component as well as also being dependent on levels of exposure to the moderator (M). Therefore, the genetic (ADV), shared environmental (CDV), and non-shared environmental (EDV) variances for DV are:
