Neighborhood social environment change in late adolescence predicts substance use in emerging adulthood

This study examines associations of changes in perceived and objective (census-based) neighborhood social environment variables during adolescence with alcohol and marijuana outcomes in emerging adulthood using two waves of data (2013–14 and 2019–20) from a cohort in Southern California (n = 1249). Increasing perceived disorganization predicted greater alcohol consequences and socialization with peers using marijuana. Decreasing objective neighborhood SES predicted fewer alcohol consequences and greater socialization with peers drinking alcohol. Unexpectedly, both decreasing and increasing perceived social cohesion predicted fewer alcohol consequences. Increasing perceived social cohesion predicted lower solitary alcohol use. Findings identify potential environmental targets to prevent substance use during the transition to emerging adulthood, but more research is warranted to understand the complex findings for alcohol consequences.