Across all cohorts, the mean TD was shorter for opioids than cocaine (Tables 1 and 2). In Yale-Penn, older age at interview was strongly associated with longer TD for both CD [hazard ratio (HR) = 0.97 per year, P = 3.51 × 10−97] and OD (HR = 0.98 per year, P = 3.02 × 10−27). EA ancestry was associated with a longer TD for CD (HR = 0.79, P = 3.70 × 10−18) and a shorter TD for OD (HR = 1.43, P = 1.20 × 10−21). Female sex was associated with longer TD for CD (HR = 0.97, P = 0.046) and shorter TD for OD (HR = 1.12, P = 0.001). Shorter TD was significantly correlated with a higher number DSM-IV dependence criteria endorsed (i.e. more severe dependence), with Pearson correlation coefficients of 0.54 and 0.53 in AAs and EAs, respectively, for OD and 0.44 and 0.48 in AAs and EAs, respectively, for CD. The distribution of DSM-4 CD and OD criteria counts in Yale-Penn are shown in Supplemental Figure 1.
