Response to reduced nicotine content cigarettes among smokers differing in tobacco dependence severity

Abstract

This study examines whether tobacco dependence severity moderates the acute effects of reducing nicotine content in cigarettes on the addiction potential of smoking, craving/withdrawal, or smoking topography. Participants (N = 169) were daily smokers with mild, moderate, or high tobacco-dependence severity using the Heaviness of Smoking Index. Following brief abstinence, participants smoked research cigarettes varying in nicotine content (0.4, 2.4, 5.2, 15.8 mg nicotine/g tobacco) in a within-subject design. Results were analyzed using repeated measures analysis of co-variance. No main effects of dependence severity or interactions with nicotine dose were noted in relative reinforcing effects in concurrent choice testing or subjective effects on the modified Cigarette Evaluation Questionnaire. Demand for smoking in the Cigarette Purchase Task was greater among more dependent smokers, but reducing nicotine content decreased demand independent of dependence severity. Dependence severity did not significantly alter response to reduced nicotine content cigarettes on the Minnesota Tobacco Withdrawal Scale nor Questionnaire of Smoking Urges-brief (QSU) Factor-2 scale; dependence severity and dose interacted significantly on the QSU-brief Factor-1 scale, with reductions dependent on dose among highly but not mildly or moderately dependent smokers. Dependence severity and dose interacted significantly on only one of six measures of smoking topography (i.e., maximum flow rate), which increased as dose increased among mildly and moderately but not highly dependent smokers. These results suggest that dependence severity has no moderating influence on the ability of reduced nicotine content cigarettes to lower the addiction potential of smoking, and minimal effects on relief from craving/withdrawal or smoking topography.

Keywords: Addiction; Cigarette smoking; Craving; Dependence severity; Heaviness of Smoking Index; Reduced nicotine content cigarettes; Reinforcement; Smoking topography; Tobacco dependence; Vulnerable populations; Withdrawal.

Fig. 1.

Results from the Cigarette Purchase Task simulating demand for cigarette smoking at escalating prices. The upper panel shows results from smokers categorized as mildly (scores = 0–2), moderately (score = 3), and highly (score = 4–6) dependent on the Heaviness of Smoking Index (HSI). Data points represent means for the three dependence severity levels at escalating prices averaging across participants and cigarette nicotine content doses (0.4, 2.4, 5.2, 15.8 mg/g). The lower panel shows results by cigarette nicotine content dose; data points represent means at escalating prices for each dose averaging across participants and dependence-severity levels. Shaded areas represent 95% CIs in the best-fit lines. Data were collected from March 23, 2015, through April 25, 2016 at University of Vermont, Brown University, and Johns Hopkins University School of Medicine.

Fig. 2.

Time-course of mean ratings on the Minnesota Tobacco Withdrawal Scale (MTWS) Desire-to-Smoke item by Heaviness of Smoking Index (HSI) severity category with results from mildly, moderately, and highly dependent smokers shown in the left, center, and right-most panels. Error bars represent ± 1 SEM. Data were collected from March 23, 2015, through April 25, 2016 at University of Vermont, Brown University, and Johns Hopkins University School of Medicine.

Fig. 3.

Upper panel: time-course of mean ratings on the brief Questionnaire of Smoking Urges (QSU) Factor 1 Scale with results from mildly, moderately, and highly dependent smokers shown in the left, center, and right-most panels. Error bars represent ± 1 SEM. Lower panel: time-course of mean ratings on the brief Questionnaire of Smoking Urges (QSU) Factor 2 Scale with results from mildly, moderately, and highly dependent smokers shown in the left, center, and right-most panels. Error bars represent ± 1 SEM. Data were collected from March 23, 2015, through April 25, 2016 at University of Vermont, Brown University, and Johns Hopkins University School of Medicine.

Fig. 4.

Effects of varying nicotine content level on mean maximum flow rate (mL/s) by Heaviness of Smoking Index (HSI) severity category with results from mildly, moderately, and highly dependent smokers shown in the left, center, and right-most panels. Maximum flow rate was measured using the Clinical Research Support System (CReSS, Lee et al., 2003). Error bars represent ± 1 SEM. Data were collected from March 23, 2015, through April 25, 2016 at University of Vermont, Brown University, and Johns Hopkins University School of Medicine.