Study Design:~Fifteen participants who currently use e-cigarettes weekly and who use or do not use tobacco cigarettes will enter a remote session study. Participants will be asked to abstain from all nicotine/tobacco products, non-nicotine electronic cigarettes, and THC containing products for 16 hours prior to four experimental sessions and will be tested in a 2x2 within-participants design with four conditions: 1) low nicotine dose (3%)/non-preferred flavor, 2) low dose/preferred flavor, 3) high dose (5%)/non-preferred flavor, and 4) high dose/preferred flavor. Order of testing will be randomized. Participants and experimenters will be blind to dose. The major outcomes will be subjective effects, e.g. liking and tests of reinforcement (choice procedures). We will require 16 hours of abstinence prior to each remote experimental session to increase the sensitivity to nicotine effects.~The consent process, experimental sessions and data collection will all be done remotely using a secure video platform. The only interaction between participants and research staff will be the curbside pick-up of study products, which will follow social distancing and mask guidelines. Participants will pick up study JUUL pods curb-side at the University of Vermont before their baseline videoconference session. Participants will be required to conduct all videoconference sessions in a place where they can legally use their JUUL.~The consent videoconference session will be conducted prior to the baseline and four experimental sessions. Participants will be assessed for COVID-19 and E-cigarette or Vaping Product Use-Associated Lung Injury (EVALI) symptoms prior to the curbside pick-up and at the start of the 5 videoconference sessions in which they will be asked to vape. During the baseline session, participants will complete a baseline questionnaire via online survey and then answer a series of questions about nicotine dependence and how many JUUL pods they would purchase at varying prices. Participants will then sample the two flavors available for JUUL -Virginia Tobacco and Menthol- using their own JUUL device. Research staff will ask participants to rate the pleasantness of each flavor and, after they have tried the flavors, participants will rank order their flavor preferences to determine their preferred flavor of the two. Finally, participants will be trained in the puffing protocol to be used in the experimental sessions.~During each experimental videoconference session, participants will report on their recent e-cigarette and tobacco product use at the start of each videoconference testing session. Those reporting non-abstinence will have their videoconference session rescheduled. During the videoconference testing sessions participants will be asked to puff either tobacco flavor 3% nicotine, tobacco flavor 5% nicotine, menthol flavor 3% nicotine, or menthol flavor 5% nicotine. After each puffing bout within each session, they will answer questions about about e-cigarette effects, e-cigarette liking and wanting, like/dislike of e-cigarette taste and e-cigarette intensity. At the end of each session, they will be asked how many JUUL pods they would purchase at varying prices.~Adverse events will be collected at the end of each videoconference session by the research assistant, who will consult with the study licensed medical provider.
The FDA has concluded that flavors (e.g. menthol) are associated with greater addiction potential in tobacco cigarettes (Gottlieb March 13, 2019). Whether the same is true for e-cigarettes and non-menthol flavors is unclear and our study should help answer this question.~Our major hypothesis is that the pharmacological effect of nicotine to induce addiction will be greater with use of a preferred e-cigarette flavor than with use of a non-preferred flavor. The pharmacological effect will be measured by how much a larger nicotine dose increases addiction potential compared to a smaller dose.