Cigarette and E-Liquid Demand and Substitution in E-Cigarette-Naïve Smokers

Behavioral economic methods allow experimental manipulation of price and examination of its effects on tobacco product purchasing. These methods may be used to examine tobacco product abuse liability and to prospectively model possible effects of price regulation. In the present study, we examined multiple measures of behavioral economic demand for cigarettes and e-liquid for use in a second-generation electronic cigarette (e-cigarette) in e-cigarette-naïve cigarette smokers. Twenty-five smokers received an e-cigarette (eGo ONE CT), sampled study e-liquid (24 mg/mL nicotine), and completed recurring sessions in which they used an experimental income to purchase real-world supplies of cigarettes and/or e-liquid. Participants also completed self-report measures of drug effects/liking. When products were available alone, we observed lower demand for e-liquid than for cigarettes. This effect was magnified when cigarettes and e-liquid were available concurrently. In additional assessments, e-liquid served as a partial substitute for cigarettes, but cigarettes did not serve as a substitute for e-liquid. Finally, participants rated e-liquid more poorly than cigarettes on several dimensions of drug effects/liking (any effects, liking, desire, and probability of continued use). We conclude that e-cigarette-naïve smokers value cigarettes more highly than e-liquid across multiple contexts and measurements. Nonetheless, participants still valued e-liquid positively and purchased it frequently, both as a substitute for cigarettes and independently of cigarettes. To understand the variables that influence transitions from exclusive smoking to either dual cigarette/e-cigarette use or exclusive e-cigarette use, future work should systematically examine the role of duration of e-liquid exposure. Public Health Significance We investigated behavioral economic demand, substitution, and self-report measures of abuse liability for cigarettes and e-liquid in e-cigarette-naïve smokers. Participants valued cigarettes more highly than e-liquid across multiple contexts and measurements. Despite these differences in valuation, participants still valued e-liquid positively, both as a substitute for cigarettes and independently of cigarettes.