%0 Journal Article %@ 1438-8871 %I JMIR Publications %V 27 %N %P e56975 %T Effectiveness of Digital Lifestyle Interventions on Depression, Anxiety, Stress, and Well-Being: Systematic Review and Meta-Analysis %A Brinsley,Jacinta %A O'Connor,Edward J %A Singh,Ben %A McKeon,Grace %A Curtis,Rachel %A Ferguson,Ty %A Gosse,Georgia %A Willems,Iris %A Marent,Pieter-Jan %A Szeto,Kimberley %A Firth,Joseph %A Maher,Carol %+ Alliance for Research in Exercise, Nutrition and Activity, University of South Australia, 108 North Terrace, Adelaide, 5000, Australia, 61 8 8302 6558, jacinta.brinsley@unisa.edu.au %K depression %K anxiety %K stress %K well-being %K mental health %K lifestyle intervention %K physical activity %K sleep %K diet %K digital health %K mobile phone %D 2025 %7 20.3.2025 %9 Review %J J Med Internet Res %G English %X Background: There is a growing body of robust evidence to show that lifestyle behaviors influence mental health outcomes. Technology offers an accessible and cost-effective implementation method for interventions, yet the study of the effectiveness of interventions to date has been specific to the mode of delivery, population, or behavior. Objective: The primary aim of this review was to comprehensively evaluate the effectiveness of digital lifestyle interventions for improving symptoms of depression, anxiety, stress, and well-being as coprimary outcomes in adults. The secondary aim was to explore the technological, methodological, intervention-specific, and population-specific characteristics that were associated with major changes in mental health outcomes. Methods: A systematic search was conducted across the MEDLINE, CINAHL, Embase, Emcare, PsycINFO, and Scopus databases to identify studies published between January 2013 and January 2023. Randomized controlled trials of lifestyle interventions (physical activity, sleep, and diet) that were delivered digitally; reported changes in symptoms of depression, anxiety, stress, or well-being in adults (aged ≥18 years); and were published in English were included. Multiple authors independently extracted data, which was evaluated using the 2011 Levels of Evidence from the Oxford Centre for Evidence-Based Medicine. Inverse-variance random-effects meta-analyses were used for data analysis. The primary outcome was the change in symptoms of depression, anxiety, stress, and well-being as measured by validated self-report of clinician-administered outcomes from pre- to postintervention. Subgroup analyses were conducted to determine whether results differed based on the target lifestyle behavior, delivery method, digital features, design features, or population characteristics. Results: Of the 14,356 studies identified, 61 (0.42%) were included. Digital lifestyle interventions had a significant small-to-medium effect on depression (standardized mean difference [SMD] −0.37; P<.001), a small effect on anxiety (SMD −0.29; P<.001) and stress (SMD −0.17; P=.04), and no effect on well-being (SMD 0.14; P=.15). Subgroup analyses generally suggested that effects were similar regardless of the delivery method or features used, the duration and frequency of the intervention, the population, or the lifestyle behavior targeted. Conclusions: Overall, these results indicate that delivering lifestyle interventions via a range of digital methods can have significant positive effects on depression (P<.001), anxiety (P<.001), and stress (P=.04) for a broad range of populations, while effects on well-being are inconclusive. Future research should explore how these interventions can be effectively implemented and embedded within health care with a concerted focus on addressing digital health equity. Trial Registration: PROSPERO CRD42023428908; https://www.crd.york.ac.uk/PROSPERO/view/CRD42023428908 %R 10.2196/56975 %U https://www.jmir.org/2025/1/e56975 %U https://doi.org/10.2196/56975