Longitudinal Associations Between Other-Sex Friendships and Substance Use in Adolescence


  • This study was supported by research grants from the Social Sciences and Humanities Research Council of Canada and from the Fonds Québécois pour la Recherche sur la Société et la Culture. The authors wish to thank the teachers and children in the Commission scolaire de Laval.

Requests for reprints should be sent to François Poulin, Département de Psychologie, Université du Québec à Montréal, Case postale 8888, Succursale Centre-ville, Montréal, Canada H3C 3P8. E-mail: poulin.francois@uqam.ca


The impact of the changes in the gender composition of friendship networks during early adolescence on substance use in late adolescence was examined. The hypothesis was that initial level and increase in the proportion of other-sex friends in the network would be associated with higher levels of substance use among girls, but not among boys. Girls and boys (n=390) were interviewed annually from ages 12 to 18 (79% retention). For both boys and girls, initial level in the proportion of other-sex friends predicted alcohol use in late adolescence, whereas it was predictive of drug use in girls only. Moreover, for girls only, a faster increase in the proportion of other-sex friends in the network predicted later use of alcohol and drugs.