Background: The study aims to (i) identify the evolving profile of endorsed alcohol expectancies (AEs) during the transition from late childhood into early adolescence, and (ii) examine the connection between such profiles and subsequent alcohol drinking and purchasing in adolescence. Methods: A prospective cohort of 928 sixth graders was recruited from 17 elementary schools in northern Taiwan in 2006 with follow-ups conducted in seventh and eighth grade. Information concerning AEs, individual characteristics, and social attributes were collected by self-administered questionnaires at baseline and in seventh grade; drinking behaviors and alcohol purchasing were assessed in eighth grade. Longitudinal latent profile and survey regression analyses were used to evaluate association estimates. Results: Three distinct profiles of positive AEs were identified: stably low (37%), stably high (35%), and increasing (28%). Regardless of childhood-onset alcohol experience, endorsing the stably high-profile AEs was associated with increased drinking occasions (adjusted relative risk [aRR] = 1.49, 95% CI = 1.24–1.80), and having the increasing-profile AEs may elevate the likelihood of alcohol purchase in adolescence (adjusted odd ratio [aOR] = 2.57, 95% CI = 1.33–4.96). Additionally, parental drinking was the most influential social factor for drinking occasions (aRR = 1.43) whereas peer drinking was prominent for alcohol purchasing (aOR = 3.06). Conclusions: The evolving profile of alcohol expectancy in late childhood may predict alcohol drinking occasion and purchasing behaviors in adolescence. Underage drinking prevention efforts should target not only pro-alcohol social environments but also cognitive constructs (e.g., alcohol expectancy).
