Hazard ratios from unadjusted and adjusted Cox regression models predicting timing of substance involvement are shown in Table 2 for EA twins. EA twins from alcoholic separated families were at highest risk of early alcohol, tobacco, cannabis and other illicit substance involvement, compared to twins from nonalcoholic intact families. Risks related to misuse were especially pronounced, with twins from alcoholic separated families at 33 times increased likelihood of first alcohol intoxication through age 10, and 3.52 times increased likelihood over ages 11-14. Twins from alcoholic separated families were at nearly 11 times increased likelihood of regular smoking through age 10, and 4.57 times increased likelihood over ages 11-14. Risks associated with intact alcoholic families were moderate, but likewise elevated across substance class, with greater risk for onset by ages 12 or 14. Effects of parental separation absent of parental alcoholism were also observed, particularly for smoking and use of cannabis or other illicit drugs. Twins from nonalcoholic families where parents separated were at nearly three times increased likelihood of smoking before age 11, and nearly two times increased likelihood over
