ASSESSING ELECTRONIC NICOTINE DELIVERY SYSTEM ABUSE LIABILITY AMONG PEOPLE WHO SMOKE CIGARETTES: IMPACT OF DEVICE CHARACTERISTICS, NICOTINE FLUX, AND FLAVOR

This clinical laboratory study utilizes subjective and behavioral economic measures to assess the abuse liability of own-brand cigarettes and six currently authorized ENDS products, examining how device characteristics, nicotine flux, and liquid flavor influence outcomes among adults who smoke cigarettes. Using a Latin-square-ordered, within-subject design, adults who smoke cigarettes (N = 30; N = 20 preferred menthol cigarettes) attended four clinical sessions: one to evaluate their own-brand cigarette and three to assess six NJOY ENDS products: 2.4% nicotine pods (~58 µg/s; tobacco and menthol flavor), 6% nicotine disposable products (~61-65 µg/s; tobacco and menthol flavor), and 5% nicotine pods (~118-123 µg/s; tobacco and menthol flavor). Outcomes included subjective effects measuring nicotine abstinence symptom suppression and acceptability and behavioral economic indices (e.g., price sensitivity, breakpoint, demand intensity, Omax, Pmax, and cross-price elasticity). Mixed ANOVAs were used to explore the impact of two within-subjects factors (nicotine flux, flavor) and one between-subjects factor (own-brand menthol cigarette status; yes vs. no). Findings revealed mixed effects of nicotine flux on nicotine abstinence symptom suppression and support for an interaction of ENDS flavor effects and menthol cigarette smoking status. Greater nicotine abstinence symptom suppression was observed when individuals used ENDS products that contrasted with their own brand cigarette menthol flavoring. For acceptability-related items, menthol-flavored ENDS were rated more positively in terms of taste, satisfaction, and cooling sensation. However, some of these effects also varied by menthol cigarette smoking status. The demand intensity and Omax behavioral economic task outcomes indicated that menthol-flavored ENDS were more preferred. For price sensitivity, a different pattern of results was observed; participants who smoked menthol cigarettes exhibited lower price sensitivity across ENDS conditions compared to those who smoked non-menthol cigarettes. In contrast, participants who smoked non-menthol cigarettes were less sensitive to price in tobacco-flavored conditions compared to menthol-flavored conditions. Results from the CP-DPT revealed most ENDS conditions substituted for OB cigarettes, with the 5% nicotine pod-based menthol-flavored product showing the strongest substitution. All ENDS served as substitutes among those who smoke menthol cigarettes, but substitution was more selective among those who smoked non-menthol cigarettes. Taken together, findings support that menthol flavoring can increase some ENDS abuse liability outcomes across nicotine flux and device type, but many of these effects were influenced by menthol cigarette smoking status. Regulatory policies aiming to reduce ENDS dependence while supporting harm reduction should account for these group differences.