Depressive symptoms predict trajectories of electronic delivery nicotine systems, cigarette, and cannabis use across 4.5 years among college students.

Background: This study examined the role of depressive symptoms on trajectories of electronic nicotine delivery systems (ENDS), cigarette, and cannabis use across 4.5 years in a sample of college students aged 18-19 at the initial study wave.

Methods: Participants were 2,264 students enrolled in one of 24 Texas colleges that participated in a multi-wave study between 2014 and 2019. Latent growth mixture models were fit to identify longitudinal trajectories for past 30-day ENDS, cigarette, and cannabis use over a 4.5-year period. Class membership was regressed on baseline depressive symptoms in multinomial regression models.

Results: Four trajectory classes were identified for each product: abstainer/minimal, decreasing, increasing, and high. Depressive symptoms were associated with a greater likelihood of belonging to the decreasing, increasing, and high trajectory classes relative to the abstainer/minimal class for all products, with the exception of the increasing ENDS class and the decreasing cannabis class.

Discussion: The findings demonstrate that there is considerable similarity across trajectories of ENDS, cigarette, and cannabis use during traditional collegiate years. Furthermore, depressive symptoms increased the likelihood of belonging to substance using trajectory classes for all products.