The 55 participants reported no lifetime use of alcohol or illicit drugs at baseline. None were cigarette smokers. Several measures were used to verify the participants’ alcohol use status at the follow-up assessment. These included information on frequency and amounts of alcohol as reported through the KSADS interview, self-reported drug and alcohol use from the Personal Experiences Inventory (43), and self-reported patterns of alcohol use from an in-house substance use interview, derived from NIAAA recommendations, that assessed current, past year, and lifetime use. Of the 55 participants, 25 continued to report no alcohol use at the follow-up assessment. The remainder (n = 30) initiated use of alcohol during the two-year follow-up interval and (at Time 2) reported regular drinking episodes during the past 12-months and during which they consumed, on average, multiple drinks several times weekly. In other words, across a two-year period, ingestion of alcohol had become part of these participants’ typical social routines. Within this group, the average age of first drink was reported to be 16.4, and escalation to regular use was reported to be on average
