Age of first use and delay to first intoxication in relation to trajectories of heavy drinking and alcohol-related problems during emerging adulthood.

BACKGROUND: Using alcohol at an early age is a well-documented risk factor for heavy drinking and the experience of a range of negative social and health consequences. However, it remains unclear if early consumption of any alcohol or early drinking to intoxication confers the greatest risk.
METHODS: Age of onset (AO) and delay to first intoxication (delay) were examined as independent predictors of heavy drinking and the experience of alcohol-related problems (problems) in a sample of incoming college freshmen (n = 1,160) who completed biannual assessments from the summer following senior year of high school through senior year of college. The sample included more women (66%) than men and a majority were Caucasian (59%). We employed latent growth curve modeling to examine self-reported AO and delay to self-defined first intoxication as predictors of the frequency of heavy drinking and problems during year 4 of college, as well as changes in these alcohol-related outcomes from high school through college.
RESULTS: An earlier AO and/or a shorter delay was associated with increased frequency of heavy drinking and problems during senior year of college. Although individuals with a later AO and/or a longer delay were at lower risk overall, they showed larger increases in heavy drinking and problems over time.
CONCLUSIONS: The findings highlight the importance of distinguishing between AO and delay to first intoxication. Delay accounted for unique variance in drinking outcomes relative to AO, and the effects of AO were stronger when delay was included as a predictor variable. Results are discussed with regard to potential mechanisms through which an early age of intoxication may confer unique risk relative to AO. The implications for cross-cultural differences in risk for problems attributable to early drinking are also discussed.