Results of an observational intervention trial: A promising harm reduction approach for persons with mental health and substance use disorders

Background : Individuals with mental health and substance use disorders smoke at much higher rates and have lower quit rates than the general population. This observational study evaluated the impact of a novel harm reduction intervention model on tobacco use in this group. Methods : The intervention included weekly support and allowed participants to set personal change goals and to use any of seven “aids” (patch, lozenge, gum, e-cigarettes, varenicline, bupropion, snus) or to decline the use of aids. The support consisted of 24 weeks of brief counseling or "SWITCH It," (8 weeks of coaching on replacing cigarettes with e-cigarettes). Primary outcomes included salivary DNA methylation, breath carbon monoxide (CO), and self-reported cigarettes per day (CPD). Eligibility required fluency in English or Spanish, salivary DNA methylation score <68, receipt of public health services, and the capacity to provide consent, but did not require an intention to quit. Qualitative data included focus groups, individual staff interviews, and counselor notes regarding barriers to change. Participants received modest compensation for interventions and data collection. Data were analyzed using Chi-square, ANOVA, t-tests, and longitudinal multiple regression models. Results : Analyses included 270 eligible individuals. There were significant increases in salivary DNA methylation scores from baseline to 6 and 12 months, and reductions over 6 months in CPD and breath CO. More weeks using e-cigarettes was associated with greater reduction in CPD and CO, but not salivary DNA methylation. Fewer years of smoking was associated with greater reduction in CPD. Most (85%) participants chose to use e-cigarettes, followed by FDA-approved nicotine replacement; very few individuals elected to use medications or snus. Participants appreciated the flexibility, lack of pressure to stop smoking, easy access to pharmacotherapy, and longer-term nature of the behavioral support. Examining cessation based on CO<6, outcomes resembled other large community-based trials in which desire to quit smoking was required. Conclusions : While the results demonstrate some promise in reducing tobacco use, it appears that most individuals require a more sustained commitment on the part of behavioral systems to enhance continued tobacco reduction. Trial Registration: ClinicalTrials.gov #NCT04523948.