A mobile healthy lifestyle intervention to promote mental health in adolescence: a mixed-methods evaluation

Abstract Background A healthy lifestyle may improve mental health. It is yet not known whether and how a mobile intervention can be of help in achieving this in adolescents. This study investigated the effectiveness and perceived underlying mechanisms of the mobile health (mHealth) intervention LIFEGOALS to promote healthy lifestyles and mental health. LIFEGOALS is an evidence-based app with activity tracker, including self-regulation techniques, gamification elements, a support chatbot, and health narrative videos. Methods A quasi-randomized controlled trial ( N = 279) with 12-week intervention period and process evaluation interviews ( n = 13) took place during the COVID-19 pandemic. Adolescents (12-15y) from the general population were allocated at school-level to the intervention ( n = 184) or to a no-intervention group ( n = 95). Health-related quality of life (HRQoL), psychological well-being, mood, self-perception, peer support, resilience, depressed feelings, sleep quality and breakfast frequency were assessed via a web-based survey; physical activity, sedentary time, and sleep routine via Axivity accelerometers. Multilevel generalized linear models were fitted to investigate intervention effects and moderation by pandemic-related measures. Interviews were coded using thematic analysis. Results Non-usage attrition was high: 18% of the participants in the intervention group never used the app. An additional 30% stopped usage by the second week. Beneficial intervention effects were found for physical activity ( χ 2 1 = 4.36, P = .04), sedentary behavior ( χ 2 1 = 6.44, P = .01), sleep quality ( χ 2 1 = 6.11, P = .01), and mood ( χ 2 1 = 2.30, P = .02). However, effects on activity-related behavior were only present for adolescents having normal sports access, and effects on mood only for adolescents with full in-school education. HRQoL ( χ 2 2 = 14.72, P < .001), mood ( χ 2 1 = 6.03, P = .01), and peer support ( χ 2 1 = 13.69, P < .001) worsened in adolescents with pandemic-induced remote-education. Interviewees reported that the reward system, self-regulation guidance, and increased health awareness had contributed to their behavior change. They also pointed to the importance of social factors, quality of technology and autonomy for mHealth effectiveness. Conclusions