Results for first alcohol intoxication are shown in Table 5. For all models, and across risk group, parent and cotwin alcohol and cannabis dependence could be equated. In the fully adjusted Model III, risk to Group 2 was significant through age 13, with offspring of unaffected parents with a substance dependent identical cotwin (Group 2a) at 7.39 times greater risk of early intoxication, compared to controls (Group 4). From age 14 onwards, risk to Group 2 was elevated, but nonsignificant. Through age 13, parental separation was uniquely associated with 3.58 times higher likelihood of early intoxication, and from age 14 onwards, 1.56 times higher likelihood.
