Social network influences on adolescent substance use: Exposure, perceptions, and ethnicity.

Adolescent social networks have been shown to be associated with use of tobacco, marijuana, and alcohol. This study seeks to replicate these associations with new data and compare perceived friend use with friend self-report as well as explore racial differences. Data were collected from up to 14 demographically diverse schools in Southern California and consisted of 23,012 surveys collected bi-annually from 9th to 12th grade with analyses conducted cross-sectionally. Regression models included fixed effects for school, and random effects for students. Results show that both perceived friend use and friend self-report were independently associated with individual use. Second, adolescents who named more friends in response to a network question were less likely to report substance use, whereas overall those who were named as friends were no more or less likely to report use. Third, students who identified as Asian ethnicity were less likely to report any substance use, but remained susceptible to peer influence on substance use. Finally, for all students, we show that being named as a friend by Asian students was protective against use of all three substances.