The prevalence of e-cigarettes has risen dramatically in the United States, and the impact of these products on public health remains controversial. Proponents of e-cigarettes argue that because e-cigarettes deliver lower levels of toxicants than conventional cigarettes, they may offer reduced health risks for current smokers who switch completely. However, while e-cigarettes appear to offer a path away from smoking for a subset of smokers, a large proportion of those who try e-cigarettes abandon them after a short trial period, or continue to use both products (i.e., dual use). Complete switching from cigarettes to e-cigarettes among those who try them is modest at best. Since the ultimate impact of e-cigarettes is likely dependent on their ability to curb cigarette smoking, it is important to understand the device characteristics (in addition to user characteristics: not studied here) that contribute to their uptake. One major and perhaps most visible device factor that determines uptake is the type of e-cigarette itself. The sheer volume of e-cigarette brands makes it impossible to test the impact of each brand (over 400 estimated brands). However, most e-cigarettes can be categorized into one of four broad types with distinct characteristics: cig-a-likes, tanks, customizable tanks, and pods.

There is strong evidence that cig-a-likes deliver less nicotine, are less satisfying, and are less likely to promote switching than other device types. Thus, these devices are not included in the proposed project. Tank devices have a nicotine delivery profile differs markedly from traditional cigarettes, and thus have also not been included here. The other two types, customizable tanks and pods, corner significant portions of the e-cigarette market and differ from each other in critical ways that would be expected to impact uptake, and thus constitute our primary focus. Customizable tanks deliver nicotine in a profile that more closely models the nicotine delivery of traditional cigarettes. These devices offer a high level of customization that allows users to adjust the device until they reach their desired sensory and nicotine delivery settings. However, the customization renders them relatively complicated to learn to use. Pods (e.g., JUUL) are the newest type of e-cigarette on the market. Pods utilize nicotine salts, rather than free-base nicotine, which the company claims allows them to deliver high levels of nicotine in a profile that is comparable to traditional cigarette. They offer no customization, making them easy to use. The combination of high nicotine delivery with increased usability may increase the relative reinforcement value of these products, resulting in greater uptake than other device types. There is almost no existing research that directly compares these device types against each other. The goal of this application is to provide a preliminary assessment comparing e-cigarette device types (customizable tanks, pods) in a head-to-head design.

In a between-subjects design, adult daily smokers (n=75) who are interested in trying e-cigarettes will be randomly assigned in 1:2:2 fashion to either a control group that receives no product (n=15), or to receive one of two types of e-cigarettes to sample over a three-week period: a) customizable tank, or b) pod, (n=30/group). The design is naturalistic in that participants receiving an e-cigarette will be told to use the e-cigarette as much or as little as they would like, allowing for assessment of self-determined uptake and reinforcement. Methods include both ecological assessments (electronic daily diaries) and experimental sessions (choice and purchase tasks). Biomarkers (expired carbon monoxide) will corroborate self-reported indices of use.