Daily variation in the patterns and characteristics of adolescent ENDS use.

Objective: Adolescents are more likely than young adults to use electronic nicotine delivery systems (ENDS), yet most of what is known is concluded from young adult ENDS use as young adults are easier to survey. Additionally, while evidence about the prevalence and trends of adolescent ENDS use comes from cross-sectional studies, ecological momentary assessment (EMA) studies provide greater detail about the ways in which adolescents vape and the environments that are favorable to adolescent vaping, providing important guidance for policy, prevention, and intervention. Method: We conducted a 2-week EMA study with 50 adolescents to assess behaviors, contexts, and characteristics of ENDS use. Given longitudinal research showing strong associations between ENDS use and use of other substances, we also examined tobacco cigarettes use, and daily concurrent use with tobacco cigarettes and marijuana. Results: There was little daily variability in motivations, willingness, and intentions, or in product characteristics. ENDS use varied by day and was more frequent on weekends, whereas cigarette use was less likely on weekends. We found daily variability in contexts and the characteristics of situations where adolescents used, which were largely social-normative, including whose device was used, which flavors were used, and where and with whom adolescents used ENDS. Unexpectedly, marijuana accompanied more than a quarter of ENDS use occasions. Conclusions: Socio-ecological context is important for explaining adolescent ENDS use and it is critical to developing adolescent ENDS prevention, intervention, and treatment resources. Prevention messaging may be most relevant and effective on weekends when youth exposure to advertising and peer influences are greatest. [ABSTRACT FROM AUTHOR]