Project Summary/Abstract Drinking use behaviors occur within a social-ecological environment where individuals are influenced by personal, interpersonal, community, societal and political factors. Adolescence is a developmentally sensitive time period where such factors may influence how frequently and consistently individuals use alcohol. While drinking patterns for young people in the US tend to be typified by escalating frequency of consumption with age, up until a decrease in use starting in the mid- to late-20s, drinking patterns across these ages are more heterogeneous than the group average would suggest. Instead, subgroups of individuals may follow a subset of drinking patterns with variations in the timing of drinking initiation, frequency of consumption, and binge drinking behaviors. While prior research has documented heterogeneous drinking trajectories within samples of young people in the US, no literature has modeled parallel trajectory groups incorporating both drinking frequency and binge drinking simultaneously. Fewer have modeled how adolescent exposures and experiences may influence trajectory membership. The proposed study advances our current understanding of alcohol use trajectories by modeling parallel trajectories of alcohol use as well as binge drinking behaviors. For aim 1, we will use dual trajectory Latent Growth Mixture Modeling (LGMM) to identify and describe trajectories of alcohol use and binge drinking from age 15 through 40 in a nationally representative sample of US adolescents followed longitudinally into adulthood. In aim 2, we will use multinomial regression approaches to investigate the independent and interactive influences of familial and environmental factors experienced in adolescence on the identified individual alcohol use trajectories. A deeper understanding of long-term alcohol use patterns and their influences into adulthood may inform future harm reduction messaging and programming. In addition, examining dual (sometimes referred to as parallel process) trajectories between frequency of drinking overall and binge drinking will help identify variations in drinking behaviors that may be masked when looking at only one behavioral outcome in isolation.