PROJECT SUMMARY/ABSTRACT Nicotine/tobacco use and pain are highly prevalent, frequently co-occur, and engender a substantial annual economic burden in medical costs and lost productivity.1-4 Rates of nicotine use are considerably higher among persons with co-occurring pain (vs. the general population),1, 2 and empirical studies have elucidated bidirectional associations between pain and nicotine/tobacco use/dependence. Nicotine can produce acute analgesic effects,5 and pain can be a potent motivator of nicotine/tobacco use for pain-coping.6 Furthermore, greater nicotine exposure has been linked to the development and exacerbation of pain.7-9 Despite increasing empirical focus on pain and nicotine use reciprocity, a majority of this research to date has focused solely on relations between pain and combustible cigarette smoking. Use of electronic cigarettes (e-cigarettes) has drastically increased over the past decade,10, 11 co-use of cigarettes and e-cigarettes is increasingly common,12 and individuals with pain may be uniquely at risk for initiation and escalation of use/co-use of e-cigarettes and cigarettes.13-15 Therefore, the goal of this proposal is to conduct the first longitudinal study of pain and use/co- use of e-cigarettes and tobacco cigarettes utilizing four waves of nationally representative cohort data collected for the Population Assessment of Tobacco and Health (PATH) Study.16 First, the proposed study will assess whether smokers with co-occurring pain (vs. no/low pain) are more likely to initiate co-use of e-cigarettes. Second, pain will be examined as a prospective predictor of (a) likelihood of cigarette and e-cigarette use/co- use, and (b) trajectories of use/co-use over time. It is hypothesized that individuals with pain will be more likely to use e-cigarettes and/or cigarettes and will increase frequency and heaviness of use across all four waves. Finally, biological sex will be examined as a moderator of the hypothesized relationships, given known sex differences in both the experience of pain and nicotine consumption. Completion of this project may advance research and clinical practice by establishing pain as a significant, yet under-recognized risk factor in the onset and escalation of nicotine consumption (via cigarettes and/or e-cigarettes). This proposal is consistent with NIDA’s stated goal of understanding the complex interactions of factors, such as medical comorbidities, that influence drug use trajectories.17 This award would provide resources and protected time to further the applicant’s training in several key areas, including increasing knowledge of pain and use of alternative nicotine/tobacco products and learning skills relevant to analysis of population-level data and trajectory modeling. The trainings, workshops, and collaborations necessary to complete the proposed project aims would be otherwise unavailable through the applicant’s clinical psychology graduate studies and placement requirements. The applic...