In the EA sample, we found a pattern of results consistent with prior literature (Grant et al., 2015; Jackson et al., 2016; Sartor et al., 2007; Thompson et al., 2008) and our hypotheses that parental divorce and parental relationship discord were associated with earlier age at first regular drinking and higher likelihood of developing AUD. In the main effects models, higher polygenic loading for alcohol problems was also associated with earlier age at first regular drinking and higher risk for developing AUD. Most previous studies in this area focus on parental marital status rather than features of parental relationships, and it is notable that the pattern of results observed in the present study was generally consistent across parental divorce and relationship discord. This suggests that exposure to parental relationship discord (i.e., a potentially more common familial adversity, even in the absence of parental divorce) appears to have similar effects as compared to those of parental divorce. Our results highlight the need to consider the influence of parental relationship discord leading up to separation/divorce, as both parental relationship dissolution (e.g., divorce)
