As expected, individuals with no substance dependence had the lowest QUANTDEP values (mean = −0.40, standard error (se) = 0.01) and those with a dependence diagnosis for all 4 substances had the highest QUANTDEP values (mean = 1.45, se = 0.06; overall F(8,1762)=659.4, p<0.0001; all pairwise Tukey-adjusted p<0.006) (Figure 1A). QUANTDEP values differed based on the substance (overall F(7,502)=32.9, p<0.0001; all pairwise Tukey-adjusted p<0.03), with individuals meeting cocaine dependence criteria having the highest mean QUANTDEP scores and those meeting criteria for alcohol dependence having the lowest (Figure 1B) of individuals meeting criteria for dependence on any substance. QUANTDEP was positively correlated with the total number of DSM-IV criteria endorsed across the 4 substances (rho = 0.88, p<0.0001).
