Given the present study’s young sample of heavy alcohol and drug users, most milestones were attained at a very early age. Fifty percent of the sample reported a first drink by age 12, compared to national surveys where a much lower proportion of youth (23–37%) reported a first drink by age 12 [1]. Although epidemiologic studies consistently indicate a peak period of risk for first alcohol use at age 18 [34], the peak period of risk in the present study was around age 15. Average progression through adjacent drinking events was relatively swift, ranging from one year (first drink, first drunk, first monthly drinking) to three years (from weekly to daily HED).
