The effects of a mobile health application on adolescent mental health during the COVID-19 pandemic: a randomized controlled study

Adolescents experienced substantial psychological distress during the COVID-19 pandemic, including elevated stress, disrupted routines, reduced peer interaction, and reduced access to in-person professional support. Mobile health (mHealth) interventions may offer accessible and scalable support for adolescents when conventional services are disrupted. This preliminary randomized controlled study evaluated whether an 8-week Mind Healer app intervention was associated with changes in self-concept and adolescent-specific stress among adolescents during the COVID-19 pandemic. Forty-nine adolescents (mean age = 16.67 years, SD = 1.08) were allocated to an intervention group (n = 26) that used the Mind Healer app for 8 weeks or a wait-list/usual-routine control group (n = 23) that did not receive app access during the study period. The app included healing music, meditation, breathing exercises, yoga, weekly health education content, reminder alarms, and photoplethysmogram (PPG)-based stress-related assessment/feedback functions. Outcomes were measured at baseline and immediately after the intervention using self-report questionnaires, including the Self-Concept Scale, Adolescent Stress Questionnaire, Perceived Stress Scale-10, Patient Health Questionnaire-9, Generalized Anxiety Disorder-7, Smartphone Dependency Scale, Effort-Reward Imbalance scale, and items on smartphone use and sleep duration. Non-parametric tests (Mann–Whitney U and Wilcoxon signed-rank tests) were used. Because baseline differences were present and no significant baseline-adjusted between-group differences were observed, the results should be interpreted as exploratory. Baseline differences were observed for self-concept (p = 0.042) and reward (p = 0.022). In within-group analyses, the intervention group showed an improvement in self-concept (p = 0.049) and a reduction in adolescent-specific stress (p = 0.048). The control group showed a significant increase in reported sleep duration (p = 0.017), with no significant changes in psychological outcomes. Exploratory baseline-adjusted ANCOVA showed no significant between-group effect for self-concept (adjusted mean difference = 1.28, 95% CI – 1.80 to 4.36; F(1, 46) = 0.70, p = 0.406, partial η² = 0.015) or adolescent-specific stress (adjusted mean difference = – 3.22, 95% CI – 9.70 to 3.26; F(1, 46) = 1.00, p = 0.323, partial η² = 0.021). Among 24 intervention participants with complete app-evaluation data, satisfaction and perceived usefulness were generally positive. The Mind Healer app shows preliminary promise as a feasible digital mental health support tool for adolescents during a public health crisis. However, the small sample size, baseline imbalances, lack of an active control, absence of significant baseline-adjusted between-group effects, and limited reporting of adherence and harms mean that the findings should be confirmed in larger, adequately powered trials.