Background: The FDA recently acquired regulatory authority over tobacco products, leading to renewed interest in whether reducing the nicotine content of cigarettes would reduce tobacco dependence in the United States. Given the association between depressive symptoms and cigarette smoking, it is important to consider whether smokers with elevated depressive symptoms experience unique benefits or negative consequences of nicotine reduction. Methods: In this secondary analysis of a randomized clinical trial that examined the effects of cigarettes varying in nicotine content over a 6-week period in non-treatment-seeking smokers, we used linear regression to examine whether baseline depressive symptom severity (scores on the Center for Epidemiologic Studies Depression Scale [CES-D]) moderated the effects of reduced-nicotine content (RNC) cigarettes, relative to normal-nicotine content (NNC) cigarettes, on smoking rates, depressive symptom severity, and related subjective and physiological measures. Results: Of the 717 participants included in this analysis, 109 (15.2%) had CES-D scores ≥ 16, indicative of possible clinical depression. Relative to NNC cigarettes, RNC cigarettes reduced smoking rates, nicotine dependence, and cigarette craving, and these effects were not significantly moderated by baseline CES-D score. A significant interaction between baseline CES-D score and cigarette condition on week 6 CES-D score was observed (p < .05); among those with CES-D scores ≥ 16 at baseline, those assigned to RNC cigarettes had lower week 6 CES-D scores than those assigned to NNC cigarettes. Among those in the lowest nicotine content conditions, biochemically confirmed compliance with the RNC cigarettes was associated with an increase in CES-D score for those with baseline CES-D scores < 16 and no change in CES-D score for those with baseline CES-D scores ≥ 16. Conclusions: These findings provide initial evidence that a reduced-nicotine standard for cigarettes may reduce smoking, without worsening depressive symptoms, among smokers with elevated depressive symptoms. Implications: This secondary analysis of a recent clinical trial examined whether depressive symptom severity moderated the effects of reduced-nicotine cigarettes on smoking and depressive symptoms. Results indicate that, regardless of baseline depressive symptoms, participants randomized to reduced-nicotine cigarettes had lower smoking rates, nicotine intake, nicotine dependence, and craving at week 6 post-randomization than those assigned to normal-nicotine cigarettes. In participants with higher baseline depressive symptoms, those assigned to reduced-nicotine cigarettes had lower week 6 depressive symptoms than those assigned to normal-nicotine cigarettes. These results suggest that a nicotine reduction policy could have beneficial effects for smokers, regardless of depressive symptom severity.
Bibliographical noteFunding Information:
The authors appreciate the important contributions of Paul Cinciripini, Steve Hecht, Joni Jensen, Tonya Lane, Joseph McClernon, Sharon Murphy, Jason Robinson, Maxine Stitzer, Andrew Strasser, Hilary Tindle, and all the students, fellows, and staff involved in the Center for the Evaluation of Nicotine in Cigarettes. The research reported in this paper was supported by the National Institute on Drug Abuse and the Food and Drug Administration Center for Tobacco Products (U54DA031659). Salary support for JWT during the preparation of this paper was also provided by P50DA036114. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or Food and Drug Administration. Portions of these data were presented at meetings of the College on Problems of Drug Dependence and the Society for Research on Nicotine and Tobacco.