Aim: To identify the mechanisms by which social interactions with classmates influence marijuana use in the transition into adolescence.Design: Using four waves of longitudinal social network data collected quarterly during the school year from the spring of 8th grade to the spring of 9th grade (2014-2016), we examine how friendship ties relate to marijuana use. Participants: 1075 adolescents were included in the present analysis. An implicit consent procedure was used: all students whose parents did not opt out of the study were eligible to participate.Setting: Participants were drawn from 12 schools with 8th graders, from five rural and two nonrural school districts in Western Oregon.Measurements: At each assessment wave participants reported on their marijuana use in the past 30 days. Using stochastic actor-oriented modeling, we examined whether classmates with similar marijuana use were more likely to select each other as friends, and if a classmate’s marijuana use was influenced by friends’ use. Findings: Past 30-day marijuana use increased in prevalence across 9th grade. Classmates with similar marijuana use were more likely to select each other as friends, and classmates were more likely to adopt similar patterns of marijuana use as their friends. This influence effect did not depend on the friend’s popularity or closeness; best friends had no more influence on marijuana use than less-close friends. Conclusion: In the transition into high school, adolescents tend to select friends who report similar recent marijuana use, and are also more likely to adopt the marijuana use patterns of their friends regardless of how close or popular they are.
@techreport{mills_diffusion_2019,
type = {Preprint},
title = {Diffusion of {Adolescent} {Marijuana} {Use} in {School} {Environments} {Following} {Recreational} {Legalization}},
institution = {PsyArXiv},
author = {Mills, Kathryn L. and Light, John M. and Rusby, Julie C. and Westling, Erika},
month = dec,
year = {2019},
doi = {10.31234/osf.io/hbz7x}
}