The Development of Drinking Trajectories Among Australian Young Adults

The present study compares drinking trajectories for two cohorts of adolescents and young adults, 10 years apart, to assess whether recent declines in adolescent drinking in Australia represent fundamental shifts in typical drinking behavior.

Six waves of annually collected, longitudinal responses from two cohorts of adolescents and young adults ages 15-25 in 2001 (n = 1,436, 48.3% male) or 2011 (n = 2,520, 48.1% male) were acquired from the Household, Income and Labour Dynamics in Australia survey (HILDA). Latent class growth analysis was used to determine the best fitting drinking trajectories for both cohorts.

Four quadratic classes were identified for the earlier cohort, and three linear for the more recent one. Light/abstaining, moderate/moderate-steady, and heavy drinking classes were observed in both cohorts, whereas an additional moderate-increasing class in the earlier cohort was absent from the recent one. The two lowest trajectories (light/abstaining and moderate/moderate-steady) appeared relatively stable across cohorts, despite an increase in light/abstaining drinkers in the recent cohort, whereas the heaviest drinkers consumed substantially less in the recent cohort than the earlier one.

We found reduced consumption across drinking patterns, suggesting that youth drinking declines are not attributable to significant shifts in drinking behaviors; rather, adolescents and young adults are drinking in a similar, albeit significantly lower, fashion. The stability of these trajectories, and the continuation of these declines into adulthood, suggest that reductions in alcohol-related harm may be likely for recent cohorts across their life course.