In contrast to the ubiquitous associations observed for externalizing disorders, internalizing conditions were associated only with later transitions, similar to other reports. (Sartor et al, 2007; Edwards et al 2014a). We did not observe a significant association with alcohol initiation, similar to some (Sartor et al, 2007; Trim et al 2010; Edwards et al 2014 b) but not all (King et al 2004) reports. Our findings are particularly credible because our data are not susceptible to limitations present in other studies, such as inclusion of participants only through the age of 14, thus likely missing the large group who initiate alcohol use in mid to late adolescence, use of a narrow definition of internalizing disorders that was limited to depression symptoms, not considering a time-varying measure of internalizing conditions, or too-small samples that might have been underpowered to detect significant associations. Further, our sample included a large proportion of offspring with parents and many other relatives with AUD who likely had high rates of externalizing and internalizing conditions that are commonly comorbid with AUD, and thus it is a sample enriched for vulnerability not only to AUD but also to its comorbid conditions.
