Depressive symptoms and the age of initiation of tobacco and marijuana use among adolescents and young adults.

Background: Studies have demonstrated important associations between depressive symptoms and tobacco and marijuana use. However, to date, it is unknown if depressive symptoms predispose youth to tobacco and marijuana use at earlier ages over time.

Methods: Data from the Texas Adolescent Tobacco and Marketing Surveillance System (TATAMS) for the years 2019-2021 (Waves 9-14) were used. Eligible samples include individuals who had never used cigarette (n=1776), e-cigarette (n=1353), or marijuana (n=1505) at basline and had complete data on covariates. Interval-censoring survival analysis was used to examine the differences in the estimated age of first use of cigarettes, e-cigarettes, and marijuana by depressive symptoms.

Results: 10th-grade cohort participants with depressive symptoms had increased risk of earlier age of first use of cigarette [AHR=1.45; 95% CI=1.02-2.04)], e-cigarette [AHR=1.65(1.27-2.15)], and marijuana [AHR=1.56(1.20-2.01)]. 12th-grade cohort participants with depressive symptoms had increased risk of earlier age of first use of cigarette [AHR=1.41(1.11-1.82), e-cigarette [AHR=1.35(1.10-1.87)] and marijuana [AHR=1.25(1.01-1.55)]. However, among the two-year post-high school cohort, depressive symptoms predicted the age of first use of marijuana only [AHR=1.34(1.13-1.60)]. Between ages 18-to-20 years, the estimated cumulative incidence of initiation almost doubled for all three products among depressive participants in 10th and 12th-grade cohorts.

Conclusions: Among 10th-grade, 12th-grade, and 2-year post-HS students, those with depressive symptoms initiate tobacco and marijuana use at earlier ages than peers without depressive symptoms. Early screening and management of depressive symptoms among adolescents and young adults may be a promising target for preventing or delaying the age of first use of substance use.