Longitudinal Associations Between Other-Sex Close Friends and Alcohol Use is a Between-, Not Within-, Person Process

BACKGROUND: Adolescents are more likely to use alcohol if close friends are characterized as majority other-sex. The extent to which the association between proportion of other-sex close friends and adolescent alcohol use is directional and/or reciprocal is unclear. Although evidence is mixed for male adolescents, higher proportion of other-sex close friends is associated with increased risk of alcohol use for female adolescents. METHODS: a multigroup framework. RESULTS: Alcohol use and proportion of other-sex close friends were relatively stable traits, with other-sex close friends' autoregressive accumulation more pronounced at later timepoints. There were no observed concurrent nor cross-lagged associations, indicating no reciprocal association within individuals. However, there was a positive between-person association, wherein adolescents with a higher proportion of other-sex close friends had, on average, greater alcohol involvement. CONCLUSIONS: Results suggest that the influence of other-sex close friends on alcohol use is a between-, not within-, person process. Thus, theory purporting a within-person reciprocal mechanism may not be pertinent within the context of other-sex close friendships.