Adverse Effects following E-Cigarette Use among Users with Psychiatric Illnesses: Risks Associated with Dual Vaping, Multiple Comorbidities and Persistent Psychiatric Issues

E-cigarettes are the most used tobacco product and are associated with significant adverse health effects. Limited research assesses the risks of adverse effects in e-cigarette users with pre-existing psychiatric illnesses. This study examines the increased risk of adverse effects among individuals with psychiatric illnesses, focusing on those with multiple medical comorbidities, persistent psychiatric symptoms, and dual users of nicotine and cannabis e-cigarettes. A sample of 851 current and former e-cigarette users with psychiatric illnesses was analyzed from a cross-sectional survey. Data included e-cigarette use, adverse events, product characteristics, behaviors, sociodemographics, medical comorbidities, and psychiatric symptoms. Dual vapers, users with multiple comorbidities, and those with persistent symptoms were identified. Logistic regression assessed the likelihood of adverse effects. 85.3% of users with psychiatric illnesses reported adverse events within six hours of vaping, including coughing, anxiety, headache, dry mouth, and lightheadedness. Among 26 significant adverse effects, dual vapers and those with more medical comorbidities or persistent psychiatric symptoms had higher odds of experiencing adverse effects after adjusting for confounders. E-cigarette users with psychiatric illnesses, particularly dual vapers and those with medical comorbidities or persistent symptoms, are at greater risk for adverse effects. Targeted public health strategies are needed to address these risks in vulnerable populations.