Frequencies of alcohol use behaviors by sex are presented in Table 1. At age 12, most (93.2%) twins responded that they had never used alcohol outside the presence of an adult. At age 14, 35.0% had used alcohol, but of them, most (76.6%) reported that they had never been intoxicated. At age 17, 12% were not alcohol users. Among users, 9.1% of the sample reported that they had never been intoxicated, 48.4% less often than once a month, 34.4% about 1 or 2 times per month, and 8.2% once per week or more, respectively. At age 22, 2.7% (n=35) were abstainers, while of those who had ever used alcohol 19.1% endorsed no alcohol dependence criteria (M=1.09, SD=1.37), and 13.5% of the sample met the criteria for DSM-IV AD (3 or more AD symptoms).
