Mechanisms of Smartphone Apps for Cigarette Smoking Cessation: Results of a Serial Mediation Model From the iCanQuit Randomized Trial

Abstract

Background Engagement with digital interventions is a well-known predictor of treatment outcomes, but this knowledge has had limited actionable value. Instead, learning why engagement with digital interventions impact treatment outcomes can lead to targeted improvements in their efficacy. Objective This study aimed to test a serial mediation model of an Acceptance and Commitment Therapy (ACT) smartphone intervention for smoking cessation. Methods In this randomized controlled trial, participants (N=2415) from 50 US states were assigned to the ACT-based smartphone intervention (iCanQuit) or comparison smartphone intervention (QuitGuide). Their engagement with the apps (primary measure: number of logins) was measured during the first 3 months, ACT processes were measured at baseline and 3 months (acceptance of internal cues to smoke, valued living), and smoking cessation was measured at 12 months with 87% follow-up retention. Results There was a significant serial mediation effect of iCanQuit on smoking cessation through multiple indicators of intervention engagement (ie, total number of logins, total number of minutes used, and total number of unique days of use) and in turn through increases in mean acceptance of internal cues to smoke from baseline to 3 months. Analyses of the acceptance subscales showed that the mediation was through acceptance of physical sensations and emotions, but not acceptance of thoughts. There was no evidence that the effect of the iCanQuit intervention was mediated through changes in valued living. Conclusions In this first study of serial mediators underlying the efficacy of smartphone apps for smoking cessation, our results suggest the effect of the iCanQuit ACT-based smartphone app on smoking cessation was mediated through multiple indicators of engagement and in turn through increases in the acceptance of physical sensations and emotions that cue smoking. Trial Registration Clinical Trials.gov NCT02724462; https://clinicaltrials.gov/ct2/show/NCT02724462

The current evidence for substance use disorder apps

“…Since participants were not engaged in other smoking cessation treatment, these findings are promising for the efficacy of iCanQuit as a stand-alone approach for smoking cessation. Furthermore, results from this study showed a significant serial mediation effect of the iCanQuit intervention, through increased acceptance of smoking cues [29 ▪▪ ]. This advances the existing evidence by being one of the only studies to unveil mechanistic effects of a mHealth intervention.…”

Smoking Cessation Smartphone App Use Over Time: Predicting 12-Month Cessation Outcomes in a 2-Arm Randomized Trial

“…Two potential reasons why iCanQuit's, but not QuitGuide's, second trajectory group had higher quit rates are most likely due to the content and structure of the iCanQuit app. Regarding content, we have published multiple studies showing that the effect of iCanQuit (but not QuitGuide) on smoking cessation was mediated by ACT-based processes of acceptance of internal cues to smoke (ie, sensations, thoughts, and emotions) [35,[45][46][47][48]. The differences in content, with iCanQuit focused on ACT versus QuitGuide focused on standard USCPG content [49], suggest that 4 weeks of engaging with ACT content that targets acceptance of internal cues is effective at improving quit rates.…”

Do medications increase the efficacy of digital interventions for smoking cessation? Secondary results from the iCanQuit randomized trial

“…Previous studies have demonstrated that ACT-based interventions promote smoking cessation by teaching adults who smoke to accept their cravings to smoke and let these cravings pass without smoking [6][7][8][9][10][11][12][13][14][15]. Compared to standard approaches for tobacco cessation, such as the USCPG that teaches avoidance of cravings, ACT-based processes teach people to observe and accept emotions and cravings that cue smoking.…”

“…We published a large ( n = 2415) randomized controlled trial (RCT) to determine the efficacy of a smartphone app for smoking cessation (iCanQuit) based on acceptance and commitment therapy (ACT) compared with a National Cancer Institute (NCI) smoking cessation app (QuitGuide) based on the US Clinical Practice Guidelines (USCPG) [5]. Previous studies have demonstrated that ACT‐based interventions promote smoking cessation by teaching adults who smoke to accept their cravings to smoke and let these cravings pass without smoking [6–15]. Compared to standard approaches for tobacco cessation, such as the USCPG that teaches avoidance of cravings, ACT‐based processes teach people to observe and accept emotions and cravings that cue smoking.…”

“…At the 12‐month follow‐up, iCanQuit was 1.5 times more efficacious than QuitGuide for smoking cessation. Moreover, results from this study showed that the effect of the intervention on smoking cessation was mediated through greater acceptance of cues to smoke [7]. iCanQuit is the first app proven to be efficacious for smoking cessation in a full‐scale RCT with long term follow‐up.…”