The phenotypic correlations across the measures of alcohol consumption and problems ranged from .45–.99 and were virtually identical to those previously reported in the full sample (Dick et al. 2011). Polychoric correlations were computed on only one twin from each pair, chosen randomly. MZ and DZ twin correlations for each of the measures were described previously (Dick et al. 2011). For the first genetic factor score (General Alcohol Consumption and Problems), scores ranged from −2.50 to 4.25 (mean=0, SD= 0.86). For the second genetic factor score (Alcohol Problems), scores ranged from −0.28 to 1.54 (mean=0, SD=0.52).
