Smoking Cessation and Mental Health According to Use of E-cigarettes and Heated Tobacco Products by Korean Adults

The health burden due to smoking, including mental health, is well documented. Previous studies reported the beneficial effect of smoking cessation on mental health. This study investigates depression and the effect of smoking cessation according to use of e-cigarettes or heated tobacco products among Korean adults. Data were obtained from the Korea Community Health Study (2019). Use of cigarettes, e-cigarettes, and heated tobacco products was assessed, and former cigarette smokers were categorized according to use of e-cigarettes and heated tobacco products. Depression, as defined by depressed mood or depressive symptoms, was assessed with the Patients Health Questionnaire-9 (PHQ-9). Study participants consisted of lifetime smokers of cigarettes (36.9%), e-cigarettes (6.0%), and heated tobacco products (7.6%). Among former smokers, complete smoking cessation was associated with decreased prevalence of depression. However, former cigarette smokers who had ever used e-cigarettes were more likely to experience a depressed mood (aOR = 1.36, 95% CI = 1.10–1.68) and depressive symptoms (aOR = 1.90, 95% CI = 1.47–2.46), compared to former smokers who had not used them. Former cigarette smokers who had ever used heated tobacco products were more likely to experience depressed mood, compared to former smokers who had not used them. Similarly, current use of e-cigarettes and current use of heated tobacco products by former smokers were both associated with higher prevalence of depressed mood and depressive symptoms. Smoking cessation altogether was associated with decreased depression in Korean adults. However, the use of e-cigarettes or heated tobacco products at any time may reduce the beneficial effect of smoking cessation.