Switching from cigarettes to IQOS: A pilot examination of IQOS-associated reward, reinforcement, and abstinence relief.

Background: It is unknown whether IQOS-associated decreases in cigarette craving, nicotine withdrawal, greater subjective reward, and relative reinforcing value predict subsequent switching from cigarettes to IQOS products.

Methods: Nontreatment-seeking adult daily smokers (n = 33; 18-65 years old) completed a within-subject pilot study consisting of a baseline ad-lib smoking period (days 1-5), two laboratory visits (days 6-7), and a two-week period where participants switch from using cigarettes to using IQOS (days 8-21). Mixed-effect modelling estimated the percentage of baseline cigarette consumption replaced by daily IQOS HeatSticks used. Predictors of use included IQOS-associated reinforcement, subjective reward, and craving and withdrawal relief.

Results: IQOS use alleviated cigarette abstinence-associated craving (change=-14.22, p < .001) but did not alleviate withdrawal symptoms. Smokers initially substituted IQOS for 59% of their average daily cigarette consumption, increasing to 87% by switch period end (B=0.02 [95%CI=0.01, 0.03], p = .002). Neither subjective reward of IQOS nor relief of cigarette craving and withdrawal symptoms were predictive of this change. By study end, IQOS consumption was 124% of regular cigarette consumption among participants with a low reinforcing value of cigarettes relative to IQOS (β = 0.03 [95%CI=0.00, 0.06], p = .049). In contrast, participants with a higher reinforcing value of smoking replaced 76% of their cigarettes with IQOS.

Conclusions: IQOS shows potential as an alternative to combustible cigarettes. However, IQOS use may result in dual-use for most smokers and increase tobacco consumption among a subgroup of smokers. These preliminary findings highlight the need for a larger investigation of the relationship between IQOS use and cigarette smoking.