A similar pattern was observed when parental separation was included in Model II, with risks associated with parent or cotwin substance dependence reducing slightly. As with Model I, risk was higher for Group 2a than Groups 1, 2b, 2c and 3, with nonsignificant differences among Groups 1, 2b, 2c and 3. Through age 10, parental separation was associated with 14.86 times higher likelihood of early drinking. From ages 11–13, risks from parental separation predicted 2.76 times greater risk, and from age 14 onwards, approximately 50% greater risk.
