Research design
This ongoing multi-site study is a prospective 12-week tobacco cessation trial (Clinical Trials ID: NCT 04228965) but is specifically enrolling and oversampling (2:1) those who co-use tobacco and cannabis. All participants (ages 18–40; N = 208) receive first-line tobacco cessation pharmacotherapy (varenicline), in addition to behavioral support (abstinence-based contingency management and cessation counseling) over the 12-week treatment period. Biochemical indices of both tobacco and cannabis use are collected throughout the 12-week treatment, in addition to self-reported use through mobile daily diaries. Cannabis use is assessed throughout the study but is not addressed as part of treatment. The goal of this study is not to evaluate the tobacco cessation treatment being implemented, but rather, tobacco treatment is being used to promote abstinence and test hypotheses regarding tobacco cessation among those who co-use cannabis. All study procedures have been approved by the Institutional Review Boards (IRB) of the Medical University of South Carolina (MUSC). Enrollment is expected to conclude in December 2023, with final primary outcome collection in March 2024.