The h2 estimate for the alcohol dependence diagnosis was significant whether or not the temporal clustering of symptoms was required (h2 = .278 ± .068, p<.001 and h2 = .173 ± .058, p=.007, respectively). In addition, the h2 estimates for 11 of the 12 alcohol dependence symptoms were also significant (p<.05). The 12th symptom (Continued drinking despite psychological problems) did not reach significance (p = .18). Despite the nonsignificant result, this final symptom was included in the follow-up linkage analyses to provide a complete examination of the symptom-level linkage data in relation to the observed linkage peaks for alcohol dependence (see Table 1 for complete results).
