Up to 300 adolescents, aged 16-25, who vape, do not smoke regularly, and want to quit vaping will be enrolled; approximately 225 eligible participants will be randomly assigned to a double blind, placebo-controlled intervention consisting of (1) varenicline or (2) identical placebo, up to 1 mg bid for 12 weeks, plus behavioral and texting support for adolescent vaping cessation or to (3) monitoring only. The primary comparison of interest is the double blind, placebo-controlled efficacy comparison of those assigned to (1) varenicline vs (2) placebo on vaping abstinence outcomes. The secondary comparison of placebo plus behavioral and texting support vs. monitoring only will estimate the efficacy of behavioral and texting support for vaping cessation in this population. The secondary comparison of varenicline plus behavioral and texting support vs monitoring only will estimate of the efficacy of varenicline treatment plus behavioral and texting support for vaping cessation in this population vs no treatment, the most common vaping cessation intervention. All participants will complete enrollment and baseline visits, and six monthly assessment visits. Those assigned to double blind intervention (study arms 1 or 2) will also complete 12 weekly behavioral support sessions. Assessors will be blind to intervention assignment (arm 1 or 2) vs monitoring only (arm 3) assignment. Among those assigned to an intervention arm, study staff and participants will be blind to active varenicline vs placebo assignment, such that among those assigned to intervention (arm 1 or 2), assignment to study drug will be double blind. For those assigned a double blind intervention arm, study staff will distribute varenicline or identical appearing placebo and give instructions use at weeks 0, 2, 4 and 8. Participants will be asked to bring all empty and unused study medication at each in-person study visit through Week 12. The enrollment visit will consist of questionnaires, diagnostic assessments, vitals, saliva and urine samples. The baseline visit will consist of questionnaires, a saliva sample for cotinine concentration, and randomization. Monthly visits will consist of interviews, questionnaires and a saliva and urine sample. Weekly treatment meetings for participants assigned to arms 1 or 2 will consist of cognitive behavioral support and questionnaires.
The study will test the hypothesis that varenicline, when added to group behavioral and texting support for vaping cessation, will improve vaping abstinence rates in adolescents dependent on vaped nicotine over placebo plus group behavioral and texting support for vaping cessation. Approximately 225 adolescents will be randomly assigned to one of three arms (1) varenicline up to 1 mg bid for 12 weeks plus behavioral and texting support for vaping cessation (2) identical appearing placebo plus behavioral and texting support and (3) monitoring only. The primary comparison will be the double-blind, placebo-controlled comparison of vaping cessation rates in those assigned to varenicline vs placebo.