Using extended nature of nurture methods, we examined parental relationship discord and parental divorce as mechanisms through which genetic risk for alcohol problems is transmitted in families. We comment on three key features of our findings. First, in European ancestry families, we found a pattern of effects consistent with our hypothesis that parental genotypes for alcohol problems impact a range of their children’s alcohol use behaviors indirectly through the environment. Specifically, nontransmitted paternal alleles and transmitted maternal alleles for alcohol problems were associated with greater parental relationship discord, which in turn was associated with increases in offspring alcohol use disorder clinical criteria, and other indicators of potential problem use, including greater maximum drinks, and an earlier age at initiation and first alcohol intoxication. Parental divorce also mediated the effects of paternal and maternal nontransmitted alleles for alcohol problems on children’s age at initiation and age at first intoxication, but not AUD clinical criterion counts nor maximum drinks.
