Introduction: No studies have examined the longitudinal relationship between e-cigarette use and elevated depressive symptoms among young adults. The main objective of the current study was to establish a potential bi-directional relationship between e-cigarette use and elevated depressive symptoms among college students in Texas, across a 1 year period of time.
Methods: A survey of 5445 college students in Texas was conducted with 6-month and 1-year follow-ups. A longitudinal cross-lagged model was used to simultaneously examine the bi-directional relationships between current, or past 30-day, e-cigarette use and elevated depressive symptoms across the three study waves. Depressive symptoms were measured using a 10-item Center for Epidemiologic Studies Depression Scale (CES-D) with a cutpoint of ≥ 10 to measure elevated depressive symptoms. Covariates included baseline age, gender, college type (2- or 4-year), and other alternative tobacco products used.
Results: E-cigarette use did not predict elevated depressive symptoms at 6-month and 1-year follow-ups. However, depressive symptoms predicted e-cigarette use at both 6-month and 1-year follow-ups.
Conclusions: The current study indicates that depressive symptoms predict subsequent e-cigarette use and not vice versa. Future studies are needed to replicate current findings and also further establish the mechanisms for causality, which could inform Food and Drug Administration regulatory planning.
Implications: There has been recent evidence for cross-sectional associations between e-cigarette use and elevated depressive symptoms and mental health problems. There have been no studies examining these associations using longitudinal designs. This study established a temporal relationship, such that elevated depressive symptoms predicted e-cigarette use 6 months later among college students. Future research is needed to establish the mechanisms of association as well as causality.
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