Mediated pathway from e-cigarette use to internalizing and externalizing mental health via polysubstance use among young adults

Abstract

ABSTRACT Objective This study examined the mediated pathways from e-cigarette use to internalizing and externalizing mental health via polysubstance use among young adults. Methods Data were drawn from the Population Assessment of Tobacco and Health, a nationally representative longitudinal study. A total of 5,042 young adults (18–24 years at baseline) who had matched data from Wave 1 to Wave 5 (2013–2019) were analyzed. Within-subject mediation analysis along with a multilevel framework assessed the mediated pathways from between time-lagged exposure (e-cigarette use at t − 1 ), time-lagged mediator (polysubstance use at t ), and outcome variables (internalizing/externalizing mental health at t + 1 ). Results Path from e-cigarette use to polysubstance use to poorer internalizing problems showed appreciable proportion of mediation (total effect: b = 0.052, 95% CI = 0.019–0.087; direct effect: b = 0.035, 95% CI = 0.001–0.070; mediated effect: b = 0.017, 95% CI = 0.011–0.025 [proportion mediated 34.0%]). Similarly, polysubstance use partially mediated the associations between e-cigarette use and externalizing problems (total effects: b = 0.050, 95% CI = 0.014–0.084; direct effect: b = 0.034, 95%CI = −0.001–0.069; mediated effects: b = 0.016, 95% CI = 0.010–0.024 [proportion mediated: 32.7%]). Conclusions Our findings imply that e-cigarette use may be detrimental to young adults’ mental health and polysubstance use patterns, underscoring the need for discouraging them from e-cigarette use.