Efficacy of a context-aware mobile app with adaptive feedback for promoting behavioral change in problematic smartphone use: Evidence from a randomized controlled trial

While problematic smartphone use (PSU) is a growing concern, evidence for randomized controlled trials on personalized digital interventions grounded in established therapeutic models remains limited, particularly regarding how user factors, such as self-regulatory functioning (SRF) and biopsychosocial well-being (BPS) interact to influence responsiveness to interventions. This study aimed to evaluate the effectiveness of a context-aware mobile app intervention designed to promote behavioral change through adaptive feedback (AF). Grounded in a cognitive behavioral therapy (CBT) framework, the AF intervention was compared with two alternative conditions: usage-statistics feedback (USF) and self-monitoring active control (AC). A three-group randomized controlled trial was conducted with 92 university students exhibiting PSU. Participants were assigned to one of the three groups (AF, USF, or AC) for an eight-week intervention. Outcome measures included smartphone usage logs, PSU scores (pre, post, 4-week follow-up), and daily self-reports of BPS and SRF. The AF group demonstrated greater reductions in smartphone time and longest-epoch duration than the AC group, whereas the USF group's effects were non-significant. The AF treatment also enhanced participants' BPS and SRF. The MANCOVA results further indicated that the AF group showed significantly lower post-intervention PSU scores than the AC group, after controlling for baseline PSU scores. Moderation analysis revealed that higher PSU weakened the positive influence of BPS on smartphone usage reduction. The findings provide strong evidence for the superiority of personalized, adaptive feedback over generic, one-size-fits-all approaches. The intervention works by enhancing self-regulatory capacity and well-being, which in turn facilitates a sustained short-term effect.