Effectiveness and Usability of Digital Slow Breathing and Detached Mindfulness Interventions in Late Adolescents: Mixed Methods Study

Abstract

Abstract Background Many adolescents experience elevated stress and anxiety; yet, access to effective psychological support is limited. Brief digital mental health interventions, such as slow breathing (SB) and detached mindfulness (DM), offer a potentially scalable approach to promoting emotion regulation in daily life. Objective This study aimed to investigate whether 1 week of daily practice with a SB or DM intervention reduced stress, anxiety, and negative metacognitive beliefs in youth, and explored participants’ experiences to inform the development of accessible, youth-tailored digital interventions. Methods A mixed method approach was used, including quantitative and qualitative data. A total of 147 university students between 16 and 19 years old were randomly allocated to the DM (n=49), SB (n=49), or passive control group (n=49). Participants who were allocated to DM or SB practiced the intervention for 1 week. Stress, anxiety, and negative metacognitive beliefs were assessed at pre- and postintervention using self-report questionnaires. The quantitative data were analyzed with linear mixed-effects models, and we explored daily changes in intervention effect. After posttest, participants were invited to focus groups to evaluate their experience with the interventions (n=37). The qualitative data were analyzed with a content analysis. Results Our results showed that a week-long DM intervention significantly reduced stress compared with the control condition. No other differences emerged for the main outcomes on pre- and postmeasurements. However, in the SB group, higher perceived usability was associated with greater reductions in stress. Qualitative findings showed that both interventions were viewed as calming, easy to use, and acceptable, while also highlighting challenges such as maintaining motivation and integrating the exercises into daily routines. Conclusions This study provides early formative evidence that brief digital interventions such as SB and DM are feasible and usable, with preliminary indication that DM intervention may support short-term stress reduction. Future research should focus on enhancing motivation and sustained engagement to maximize the effectiveness of digital mental health tools for late adolescents.