Leveraging the cigarette purchase task to understand relationships between cumulative vulnerabilities, the relative reinforcing effects of smoking, and response to reduced nicotine content cigarettes

We examined if the relative-reinforcing effects of smoking increase with greater cumulative vulnerability and whether cumulative vulnerability moderates response to reduced nicotine content cigarettes. Participants were 775 adults from randomized clinical trials evaluating research cigarettes differing in nicotine content (0.4, 2.4, 15.8 mg/g). Participants were categorized as having low (0–1), moderate (2–3), or high (≥4) cumulative vulnerability. Vulnerabilities included rural residence, opioid use disorder, affective disorder, low educational attainment, poverty, unemployment, and physical disability. We used the cigarette purchase task (CPT) to assess the relative-reinforcing effects of participants' usual-brand cigarettes at baseline and study cigarettes during the 12-week trial. The CPT is a behavioral-economic task wherein participants estimate likely smoking (demand) over 24 h under escalating cigarette price. Demand is characterized by two factors: Amplitude (demand volume at zero/minimal price) and Persistence (demand sensitivity to price). Greater cumulative vulnerability was associated with greater demand Amplitude (F[2709] = 16.04,p <.0001) and Persistence (F[2709] = 8.35,p =.0003) for usual-brand cigarettes. Demand Amplitude for study cigarettes increased with increasing cumulative vulnerability (F[2619] = 19.59, p <.001) and decreased with decreasing nicotine content ([4879] = 5.45, p <.001). The only evidence of moderation was on demand Persistence (F[8867] = 2.00,p =.04), with larger reductions at the 0.4 mg/g compared to 15.8 mg/g doses among participants with low compared to moderate or high cumulative vulnerability. The relative-reinforcing effects of smoking clearly increase with greater cumulative vulnerability. Reducing nicotine content would likely reduce demand Amplitude across cumulative-vulnerability levels but reductions in demand Persistence may be more limited among those with greater cumulative vulnerability.