The current analyses did not include additional characteristics related to alcohol problems, such as the age of onset of drinking. There are several indications that the age of onset may not be a major issue in these analyses. First, LR and the age of first full drink only correlated at -.05 in the current sample, which while significant in this large group, explains only a small proportion of the variance. Second, the cross-sectional relationship between LR and the most relevant dependent variable, the maximum number of drinks, is about .50 in both subjects as young as age 12 and for subjects almost age 20, with the latter consisting mostly of males and females with later onsets (Schuckit et al., 2008b, 2009a). This indicates that LR and heavy drinking are relatively closely linked despite differences in the age at which drinking began. Third, an early age of onset is relatively closely linked to conduct problems and similar externalizing behaviors, but there is little evidence that LR and externalizing symptoms are closely related (Schuckit and Smith, 2006; Schuckit et al., 2000). These
