Same-Sex Friendship, School Gender Composition, and Substance Use: A Social Network Study of 50 European Schools

ABSTRACT

Background: Other-sex friendship (girls with boy friends, boys with girl friends) has been associated with substance use, but how the gender composition of schools influences substance use has not been known. Objectives: We analyzed the influence of other-sex friendship on substance use and took into account the proportion of each gender group at the schools, and hypothesized that other-sex friendship is associated with higher levels of substance use and that schools with a majority of males have higher levels of use than female-majority schools. Methods: In 2013, a social network survey was carried out in six European cities. In each city, schools were selected and 11,015 adolescents (aged 14-16) were recruited (participation rate = 79.4%). We collected data on smoking, binge drinking, cannabis use, and peer group composition. Results: Other-sex friendship was associated with smoking, binge drinking, and cannabis use for girls and with smoking for boys. Substance use was more frequent in schools with a majority of males. Conclusions/Importance: Adolescent girls are best protected from substance use if they are in gender-balanced schools, but in same-sex friendship. This offers new perspectives on gender mixing at school. In schools with a majority of boys, more attention should be paid to girls, and gender-specific health promotion programs should be implemented. This European study is the first to take into account both individual (other-sex friendship) and contextual (gender composition of schools) gender interactions. It confirms previous studies on other-sex friendship, while shedding light on the influence of gender-normative contexts on substance use.

KEYWORDS:

• Other-sex friendship
• same-sex friendship
• gender
• high school
• substance use
• tobacco
• alcohol
• cannabis
• adolescents
• binge drinking

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Acknowledgments

This study was financed by the European Commission's 7th Research Framework Programme. All authors participated in the writing of the manuscript. Preliminary results of this manuscript have been presented in an oral presentation at the Sunbelt 2015 conference.

Contribution of authors

AG: conceived the study, performed the statistical analysis, and coordinated and drafted the manuscript. AK: participated in the design of the study and helped to draft the manuscript. MK: participated in the design of the study and helped to draft the manuscript. MR: participated in the design of the study and helped to draft the manuscript. AR: participated in the design of the study and helped to draft the manuscript. BF: participated in the design of the study and helped to draft the manuscript. VL: conceived the study, participated in its design and coordination, and helped to draft the manuscript. All authors have read and approved the final manuscript.

Ethical approval

“All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards”.

Informed consent: “Informed consent was obtained from all individual participants included in the study.”