Prospective longitudinal relations among frequent social media use, nicotine vaping and experiencing internalizing mental health problems.

Aims: To compare four a priori rival mediated pathways of frequent social media use, electronic nicotine delivery systems (ENDS) use and internalizing mental health (MH) problems across five waves of nationally representative data. Design, setting and participants: This was a longitudinal study using data drawn from waves 2–5 (October 2014–November 2019) of the Population Assessment of Tobacco and Health Study, a nationally representative cohort study spanning approximately 5 years, conducted in the United States. The analytical sample of participants included those who were aged 12–14 years at wave 2 and who provided data in subsequent waves until wave 4.5 (n = 4627, 69.7% were White and 51.4% were male). Measurements: Frequent social media use (several times a day), ENDS use (past 30‐day use) and internalizing MH problems (endorsed symptoms on four items in the past year) were dichotomized for analysis. Findings The weighted proportions of the three key variables increased over time. From wave 2 to wave 5, frequent social media use grew from 56.9 to 77.2%; internalizing MH problems from 18.9 to 29.0%; and ENDS use from 1.4 to 11.4%. In weighted logistic regressions using generalized linear mixed models with random effects, there was a significant within‐person association between frequent social media use at time t and greater ENDS use at t + 1 [adjusted odds ratio (aOR) = 1.87; 95% confidence interval (CI) = 1.47, 2.37] and worsened internalizing MH problems at t + 1 (aOR = 1.19; 95% CI = 1.04, 1.37). A model‐based causal mediation analysis and marginal structural models were fitted to estimate the average causal mediation effect. Among all four examined mediation pathways throughout the three constructs, partial mediation was observed, and all the pathways were significant for both boys and girls. Sex differences did not emerge in the examined prospective mediated pathways. Conclusions: Among youth in the United States, frequent social media use appears to mediate the prospective association between experiencing internalizing mental health problems and using electronic nicotine delivery systems. [ABSTRACT FROM AUTHOR]