Cannabis-Tobacco Co-Use Treatment Study

Participants will be randomized 1:1 to varenicline or matched placebo. The standard dose titration schedule will be used, which includes 0.5 mg once per day (q.d.) on Days 1-3, 0.5 mg twice per day (b.i.d.) on Days 4-7, and 1 mg b.i.d. starting on Day 8. Dosing of 2 mg per day will be maintained for the next 11 weeks.

Research staff will provide skills-based counseling at weekly visits. Weekly counseling sessions will include discussion of online intervention modules, while providing skills-based strategies focused on enlisting social support, recognizing triggers, managing craving/withdrawal/stress, etc. Staff will use motivational enhancement techniques to address tobacco cessation, cannabis reduction or abstinence, and medication adherence.

Participants will have access to online modules addressing tobacco and cannabis co-use to support cessation and/or reduction. Content includes 12 virtual modules combining cognitive behavioral therapy (CBT) and motivational enhancement (MET) to address tobacco, cannabis, and their co-use.