First drink to first drunk: age of onset and delay to intoxication are associated with adolescent alcohol use and binge drinking

Background: Quickly progressing from initiating alcohol use to drinking to intoxication recently was identified as a novel risk factor for hazardous drinking in college students (ME Morean et al. [2012] Alcohol Clin Exp Res, 36, 1991-1999). The current study evaluated the risk associated with age of onset (AO) and delay to first intoxication (Delay) in a high school sample.

Methods: Adolescent drinkers (N = 295, age 16.29 [1.14], 55.3% female, 80.3% Caucasian, AO = 13.51 [2.29] years, Delay = 0.80 [1.43] years) completed an anonymous survey about their substance use in February of 2010. Self-report questions assessed AO and age of first intoxication (AI) (i.e., "How old were you the first time you tried alcohol/got drunk?") and past-month alcohol use/binge drinking (i.e., How often did you drink alcohol/drink ≥5 drinks?).

Results: Bivariate correlations indicated that AO was positively correlated with AI and inversely correlated with Delay, the frequency of any drinking, and the frequency of binge drinking. When considered alone, Delay was not significantly correlated with either alcohol use outcome. In contrast, hierarchical regression analyses indicated that when considered in concert, an earlier AO and a shorter Delay were each associated with heavier drinking (any drinking adjusted R(2) = 0.08; binge drinking R(2) = 0.06, p-values <0.001) beyond demographic characteristics. Two-way interactions among study variables were nonsignificant, suggesting that AO and Delay conferred risk similarly by racial/ethnic status, gender, and grade in high school.

Conclusions: When considered simultaneously, both an early AO and a quick progression to drinking to intoxication appear to be important determinants of high school student drinking. In addition to continuing efforts to postpone AO, efforts designed to delay intoxication may modulate alcohol-related risk associated with early drinking.