Predicting alcohol misuse among Australian 19-year-olds from adolescent drinking trajectories

Background: Alcohol use in adolescence predicts future alcohol misuse. However, the extent to which different patterns of adolescent use present risk remains unclear. Objectives: This study investigated how adolescent trajectories of alcohol consumption during the school years predict alcohol misuse at age 19 years. Methods: Data were drawn from 707 students from Victoria, Australia, longitudinally followed for 7 years. Five alcohol use trajectories were identified based on the frequency of alcohol use from Grade 6 (age 12 years) to Grade 11 (age 17 years). At age 19 years, participants completed measures indicating Heavy Episodic Drinking (HED), dependency – Alcohol Use Disorders Identification Test (AUDIT) and social harms. Results: At 19 years of age, 64% of participants reported HED, 42% high AUDIT scores (8+), and 23% social harms. Participants belonging to a steep escalator trajectory during adolescence had twice the odds at 19 years of age of high AUDIT scores and social harms, and three times greater odds of HED than participants whose alcohol use slowly increased. Stable moderate consumption was also associated with an increased risk of HED compared to slowly increasing use. Abstinence predicted a reduced likelihood of all forms of misuse at 19 years of age compared to slowly increased alcohol use. Conclusions: Trajectories of drinking frequency during adolescence predict alcohol misuse at age 19 years. Although rapid increasing use presents the greatest risk, even slowly increasing drinking predicts increased risk compared to abstinence. The findings indicate that alcohol policies should recommend nonuse and reduced frequency of use during adolescence.