Therapeutic contact intensity as an adjunct to a cognitive behavioral smoking cessation app: protocol for a randomized controlled trial

Background Smoking cessation improves the health and well-being of people who smoke. It also benefits society, given the high economic and personal costs of smoking-related diseases. With the emergence of new digital technologies, there has been a shift in the delivery of smoking cessation interventions, moving from the traditional in-person treatments to remote digital interventions. In particular, despite a tremendous increase in the number of smoking cessation mobile applications, very few have been empirically tested. Additionally, it remains unclear whether therapeutic contact could improve smoking abstinence outcomes. Therefore, the overall goal of this study is to assess the efficacy of a newly developed app adapted from an in-person efficacious cognitive-behavioral treatment (CBT) for smoking cessation compared to the app in combination with different doses of therapeutic contact. Methods We will conduct a randomized controlled trial (RCT) with a sample of 420 individuals seeking smoking cessation treatment at the Smoking and Addictive Disorders Unit of the University of Santiago de Compostela (Spain). Participants will be randomly assigned to: (1) 8 weeks of smoking cessation app (Only app; n = 140); (2) 8 weeks of smoking cessation app + 8 weekly sessions of group CBT delivered via video calls (High intensity; n = 140); or (3) 8 weeks of smoking cessation app + 4 biweekly sessions of group CBT delivered via video calls (Low intensity; n = 140). Discussion We expect that the high intensity therapeutic contact group will result in higher 7-day point-prevalence smoking abstinence (validated via carbon monoxide) at the end of treatment and 3-, 6-, and 12-month post-treatment, compared to the other two conditions. This study will be the first RCT evaluating the dose of therapeutic contact needed when using a smoking cessation app. Findings will contribute to improving the efficacy and reach of smoking cessation treatments. Trial registration ClinicalTrials.gov number: NCT06900985 registered on March 21, 2025. Protocol version 1.0.