Abstract
<title>Abstract</title> <p>Purpose. The 2024 National Survey on Drug Use and Health (NSDUH) introduced the seven-item Generalized Anxiety Disorder scale (GAD-7) for adults, enabling the first nationally representative comparison of nicotine versus tetrahydrocannabinol (THC) e-cigarette use with anxiety symptoms. Methods. Cross-sectional analysis of adults aged ≥ 18 years in the 2024 NSDUH public-use file (n = 47,299; weighted ≈ 262 million). Past-month e-cigarette use was classified as none, nicotine-only, THC-only, or dual use. The outcome was moderate-to-severe anxiety symptoms (GAD-7 ≥ 10). Survey-weighted logistic regression estimated crude and adjusted odds ratios (aOR) controlling for demographic, socioeconomic, insurance, and past-month cigarette and alcohol covariates; pre-specified sensitivity models additionally adjusted for marijuana use and major depressive episode. Results. Moderate-to-severe anxiety prevalence was 7.4% overall, and 5.9%, 15.8%, 17.3%, and 21.6% among non-vapers, nicotine-only, THC-only, and dual vapers. Nicotine-only (aOR 1.65, 95% CI 1.39–1.95), THC-only (aOR 2.45, 1.90–3.15), and dual (aOR 2.23, 1.82–2.73) use were each associated with higher odds of anxiety symptoms (joint p = 3.1×10⁻⁹). After additional adjustment for marijuana use and depression, the nicotine-only association persisted (aOR 1.50, 1.24–1.80), THC-only was borderline (aOR 1.51, 1.06–2.15), and dual use was non-significant (aOR 1.21, 0.88–1.65). Associations were stronger in women (interaction p = 0.012). Conclusion. Past-month e-cigarette use was associated with higher odds of moderate-to-severe anxiety symptoms. The nicotine-only association was most robust; the THC-vaping association was largely shared with marijuana use and depression, although adjusting for marijuana use may over-control because THC vaping is itself a form of marijuana use. Cross-sectional associations cannot establish causation.</p>