Effect of e-cigarettes for smoking cessation on depressive and anxiety symptoms: Secondary analysis of a randomized controlled trial

Objective: This study aims to assess differences in depressive and anxiety symptoms at 6-month follow-up in a smoking cessation trial using e-cigarettes as quitting aids. Methods: We conducted a secondary analysis of the Swiss multicentre ESTxENDS smoking cessation randomized controlled trial (RCT) assessing differences in depressive (Patient Health Questionnaire-9, PHQ-9, range: 0-27) and anxiety symptoms (General Anxiety Disorder-7, GAD-7, range: 0-21) at 6-month follow-up comparing participants who received e-cigarettes to those who received smoking cessation counseling alone. Results: Of 1244 participants 913 completed the PHQ-9 and 884 the GAD-7 at 6-month follow-up. Mean PHQ-9 scores (SD) at 6 months for the intervention group were 3.7 (3.9), control group: 4.0 (4.2); mean GAD-7 scores (SD) at 6 months for the intervention group were 4.6 (4.3), control group: 4.6 (4.4). Multivariable analyses showed no evidence of a clinically relevant intervention effect on the PHQ-9 [coefficient- 0.101, 95 % CI-0.182 to-0.019, p = .016, corresponding to a 0.9 decrease of the original PHQ-9 score] and the GAD-7 scores [coefficient- 0.056, 95 % CI-0.135 to 0.022, p = .160] in the main adjusted models. Conclusions: Among smokers who participated in the ESTxENDS smoking cessation trial, we found distribution of e-cigarettes for smoking cessation in addition to standard counseling compared to counseling alone had no clinically relevant effect on depressive or anxiety symptoms at 6-month follow-up. Trial Registration: ClinicalTrials NCT03603340