Objective

The present longitudinal study examines how age of alcohol initiation and regular use (weekly drinking for ≥6 months) relates to adolescent physiological development, social behaviors, psychological functioning, and substance use patterns. Method: Data are drawn from a prospective sample of 295 youth (42% female) who completed a 15-year longitudinal study. The current investigation uses data collected at 4 timepoints from ages 12-19. Results: Latent growth modeling revealed earlier age of alcohol initiation is associated with (1) a more advanced stage of pubertal development, more self-reported dating experience, and greater externalizing behaviors at ages 12-13 (study entry); (2) a slower rate of change in pubertal development; and (3) greater rate of increase in externalizing and internalizing symptoms from ages 12 to 19. These relationships were not moderated by gender. Conclusion: Early alcohol initiation appears to be associated with early onset pubertal development and dating behaviors. Over time, early alcohol use behaviors may delay pubertal development while exacerbating psychological risk behaviors (i.e. externalizing and internalizing behaviors). These findings suggest the importance of delaying alcohol initiation and may be beneficial for improving existing adolescent substance use prevention efforts.