Marcus, M., Yasamy, M. T., van Ommeren, M., Chisholm, D., & Saxena, S. Depression: A global public health concern. World Health Organization https://doi.org/10.1037/e517532013-004 (2012).
World mental health today: latest data. World Health Organization https://www.who.int/publications/i/item/9789240113817 (2025).
Cuijpers, P. Targets and outcomes of psychotherapies for mental disorders: an overview. World Psychiatry 18, 276–285 (2019).
Kazdin, A. E. & Blase, S. L. Rebooting psychotherapy research and practice to reduce the burden of mental illness. Perspect. Psychol. Sci. 6, 21–37 (2011).
Coombs, N. C., Meriwether, W. E., Caringi, J. & Newcomer, S. R. Barriers to healthcare access among U.S. adults with mental health challenges: a population-based study. SSM – Popul. Health 15, 100847 (2021).
Ramos, G., Hernandez-Ramos, R., Taylor, M. & Schueller, S. M. State of the science: using digital mental health interventions to extend the impact of psychological services. Behav. Ther. https://doi.org/10.1016/j.beth.2024.04.004 (2024).
Jardine, J. et al. Between rhetoric and reality: real-world barriers to uptake and early engagement in digital mental health interventions. ACM Trans. Comput. Hum. Interact. 31, 27:1–27:59 (2024).
Krukowski, R. A. et al. Digital health interventions for all? Examining inclusivity across all stages of the digital health intervention research process. Trials 25, 98 (2024).
Yardley, L. et al. Understanding and promoting effective engagement with digital behavior change interventions. Am. J. Prev. Med. 51, 833–842 (2016).
Schleider, J., Dobias, M. L., Sung, J. Y. & Mullarkey, M. C. Future directions in single-session youth mental health interventions. J. Clin. Child Adolesc. Psychol. 49, 264–278 (2020).
Schleider, J. et al. Single-session interventions for mental health problems and service engagement: umbrella review of systematic reviews and meta-analyses. Annu. Rev. Clin. Psychol. https://doi.org/10.1146/annurev-clinpsy-081423-025033 (2025).
Schleider, J. & Beidas, R. S. Harnessing the single-session intervention approach to promote scalable implementation of evidence-based practices in healthcare. Front. Health Serv. 2, 997406 (2022).
Dobias, M. L., Morris, R. R. & Schleider, J. Single-session interventions embedded within Tumblr: acceptability, feasibility, and utility study. JMIR Form. Res. 6, e39004 (2022).
Ghosh, A., McDanal, R. & Schleider, J. L. Digital single-session interventions for child and adolescent mental health: evidence and potential for dissemination across low- and middle-income countries. Adv. Psychiatry Behav. Health 3, 129–138 (2023).
Schleider, J. & Weisz, J. R. Can less be more? The promise (and perils) of single-session youth mental health interventions. Behav. Ther. 40, 256–261 (2017).
Ball, J., Thompson, Z., Meiser-Stedman, R. & Chiu, K. Self-Administered single session interventions for mental health in young people: a systematic review and meta-analysis. SSRN https://doi.org/10.2139/ssrn.4856261 (2024).
Lorenzo-Luaces, L. et al. A pragmatic randomized controlled trial of stepped care cognitive-behavioral therapy for internalizing distress in adults. Cogn. Ther. Res. 48, 998–1013 (2024).
Lorenzo-Luaces, L. & Howard, J. Efficacy of an unguided, digital single-session intervention for internalizing symptoms in web-based workers: randomized controlled trial. J. Med. Internet Res. 25, e45411 (2023).
Mullarkey, M. et al. Web-based single session intervention for perceived control over anxiety during COVID-19: randomized controlled trial. JMIR Ment. Health 9, e33473 (2022).
Dodge, K. A. et al. Population mental health science: guiding principles and initial agenda. Am. Psychol. 79, 805–823 (2024).
Prentice, D. A. & Miller, D. T. When small effects are impressive. Psychol. Bull. 112, 160–164 (1992).
Manvelian, A. et al. A practical guide to adapting evidence-based treatments into digital single-session interventions for youth. Preprint at https://doi.org/10.31234/osf.io/vjgxr_v1 (2025).
Schleider, J., Abel, M. R. & Weisz, J. R. Do immediate gains predict long-term symptom change? Findings from a randomized trial of a single-session intervention for youth anxiety and depression. Child Psychiatry Hum. Dev. 50, 868–881 (2019).
Cohen, K., Dobias, M., Morris, R. & Schleider, J. Improving uptake of mental health crisis resources: randomized test of a single-session intervention embedded in social media. J. Behav. Cogn. Ther. 33, 24–34 (2023).
Osborn, T. L. et al. Single-session digital intervention for adolescent depression, anxiety, and well-being: Outcomes of a randomized controlled trial with Kenyan adolescents. J. Consult. Clin. Psychol. 88, 657–668 (2020).
Kaveladze, B., Ghosh, A., Funkhouser, C. J., Schueller, S. M. & Schleider, J. L. Longer single-session interventions may not be better: evidence from two randomized controlled trials with online workers facing mental-health struggles. Clin. Psychol. Sci. https://doi.org/10.1177/21677026251358836 (2025).
Yeager, D. S. & Dweck, C. S. Mindsets that promote resilience: when students believe that personal characteristics can be developed. Educ. Psychol. 47, 302–314 (2012).
Gualano, M. R. et al. The long-term effects of bibliotherapy in depression treatment: systematic review of randomized clinical trials. Clin. Psychol. Rev. 58, 49–58 (2017).
Schleider, J., Dobias, M., Sung, J., Mumper, E. & Mullarkey, M. C. Acceptability and utility of an open-access, online single-session intervention platform for adolescent mental health. JMIR Ment. Health 7, e20513 (2020).
Ryan, R. M. & Deci, E. L. Self-determination theory and the facilitation of intrinsic motivation, social development, and well-being. Am. Psychol. 55, 68–78 (2000).
Voelkel, J. G. et al. Megastudy testing 25 treatments to reduce antidemocratic attitudes and partisan animosity. Science 386, eadh4764 (2024).
Milkman, K. L. et al. Megastudies improve the impact of applied behavioural science. Nature 600, 478–483 (2021).
Milkman, K. L. et al. A 680,000-person megastudy of nudges to encourage vaccination in pharmacies. Proc. Natl Acad. Sci. USA 119, e2115126119 (2022).
Schleider, J. et al. A randomized trial of online single-session interventions for adolescent depression during COVID-19. Nat. Hum. Behav. 6, 258–268 (2022).
Protzko, J. Invariance: what does measurement invariance allow us to claim?. Educ. Psychol. Meas. 85, 458–482 (2025).
Hlynsson, J. I., Skúlason, S., Andersson, G. & Carlbring, P. Why are we still using the PHQ-9? A historical review and psychometric evaluation of measurement invariance. Psychiatr. Q. https://doi.org/10.1007/s11126-025-10208-9 (2025).
Luong, R. & Flake, J. K. Measurement invariance testing using confirmatory factor analysis and alignment optimization: A tutorial for transparent analysis planning and reporting. Psychol. Methods 28, 905–924 (2023).
Lee, M. R. & Shen, M. Winner’s curse: bias estimation for total effects of features in online controlled experiments. In Proc. 24th ACM SIGKDD International Conference on Knowledge Discovery & Data Mining 491–499 (Association for Computing Machinery, 2018).
Plessen, C. Y., Panagiotopoulou, O. M., Tong, L., Cuijpers, P. & Karyotaki, E. Digital mental health interventions for the treatment of depression: a multiverse meta-analysis. J. Affect. Disord. 369, 1031–1044 (2025).
Steinberg, J. S. et al. Randomized trial testing a self-guided digital mental health intervention teaching calming skills for Ukrainian children. NPJ Ment. Health Res. 4, 20 (2025).
Morris, R. R., Schueller, S. M. & Picard, R. W. Efficacy of a web-based, crowdsourced peer-to-peer cognitive reappraisal platform for depression: randomized controlled trial. J. Med. Internet Res. 17, e72 (2015).
Mrazek, A. J. et al. Attention training improves the self-reported focus and emotional regulation of high school students. Technol. Mind Behav. 3, 4 (2022).
Kumarasamy, V., Goodfellow, N., Ferron, E. M. & Wright, A. L. Evaluating the problem of fraudulent participants in health care research: multimethod pilot study. JMIR Form. Res. 8, e51530 (2024).
Douglas, B. D., Ewell, P. J. & Brauer, M. Data quality in online human-subjects research: comparisons between MTurk, Prolific, CloudResearch, Qualtrics, and SONA. PLoS ONE 18, e0279720 (2023).
Chapkovski, P., Peer, E. & Brandt, E. From WEIRD to GREAT? Exploring data quality of global platforms for online research. Preprint at https://doi.org/10.31234/osf.io/xvfqn (2024).
Protzko, J. The Online Volunteer Subject. Preprint at https://doi.org/10.31234/osf.io/gh2ck (2022).
Bryan, C. J., Tipton, E. & Yeager, D. S. Behavioural science is unlikely to change the world without a heterogeneity revolution. Nat. Hum. Behav. 5, 980–989 (2021).
Baumel, A., Muench, F., Edan, S. & Kane, J. M. Objective user engagement with mental health apps: systematic search and panel-based usage analysis. J. Med. Internet Res. 21, e14567 (2019).
Nafziger, J. Spillover effects of nudges. Econ. Lett. 190, 109086 (2020).
Arnautovska, U. & Milton, A. The era of digital mental health interventions: we know they can be effective but are they also safe?. BJPsych Open 11, e89 (2025).
Garrey, S. K., Takemoto, E., Petrsoric, L. & Gargano, L. M. Self-Efficacy and mental health help-seeking behavior of World Trade Center Health Registry enrollees, 2015–2016. Int. J. Environ. Res. Public. Health 19, 7113 (2022).
McDermott, R. C. et al. Hope for help-seeking: a positive psychology perspective of psychological help-seeking intentions. Couns. Psychol. 45, 237–265 (2017).
Rizvi, S. L. et al. Randomized clinical trial of a brief, scalable intervention for mental health sequelae in college students during the COVID-19 pandemic. Behav. Res. Ther. 149, 104015 (2022).
Wakefield, S. et al. Improving Access to Psychological Therapies (IAPT) in the United Kingdom: a systematic review and meta-analysis of 10-years of practice-based evidence. Br. J. Clin. Psychol. 60, e12259 (2021).
Kaveladze, B. T. Using Brief Internet Interventions to Challenge Loneliness at Scale (UC Irvine, 2023).
Groot, J. et al. The effectiveness of fully automated digital interventions in promoting mental well-being in the general population: systematic review and meta-analysis. JMIR Ment. Health 10, e44658 (2023).
Hartman, R. et al. Introducing Connect by CloudResearch: advancing online participant recruitment in the digital age. Preprint at https://doi.org/10.31234/osf.io/ksgyr (2023).
Palan, S. & Schitter, C. Prolific.ac—a subject pool for online experiments. J. Behav. Exp. Finance 17, 22–27 (2018).
Qualtrics (Qualtrics, 2005).
Kroenke, K., Spitzer, R. L. & Williams, J. B. W. The PHQ-9. J. Gen. Intern. Med. 16, 606–613 (2001).
Terides, M. D. et al. The frequency of actions and thoughts scale: development and psychometric validation of a measure of adaptive behaviours and cognitions. Cogn. Behav. Ther. 45, 196–216 (2016).
Snyder, C. R. et al. Development and validation of the State Hope Scale. J. Pers. Soc. Psychol. 70, 321–335 (1996).
Perczel Forintos, D., Rózsa, S., Pilling, J. & Kopp, M. Proposal for a short version of the Beck Hopelessness Scale based on a national representative survey in Hungary. Community Ment. Health J. 49, 822–830 (2013).
Eddington, K. M., Dozois, D. J. A. & Backs-Dermott, B. J. Evaluation of the internal consistency, factor structure, and validity of the Depression Change Expectancy Scale. Assessment 21, 607–617 (2014).
Perski, O. & Short, C. E. Acceptability of digital health interventions: embracing the complexity. Transl. Behav. Med. 11, 1473–1480 (2021).
Devilly, G. J. & Borkovec, T. D. Psychometric properties of the credibility/expectancy questionnaire. J. Behav. Ther. Exp. Psychiatry 31, 73–86 (2000).
Adler, N. E., Epel, E. S., Castellazzo, G. & Ickovics, J. R. Relationship of subjective and objective social status with psychological and physiological functioning: preliminary data in healthy white women. Health Psychol. 19, 586–592 (2000).
Feingold, A. Effect sizes for growth-modeling analysis for controlled clinical trials in the same metric as for classical analysis. Psychol. Methods 14, 43–53 (2009).
Bates, D., Mächler, M., Bolker, B. & Walker, S. Fitting linear mixed-effects models using lme4. J. Stat. Softw. 67, 1–48 (2015).
Kuznetsova, A., Brockhoff, P. B. & Christensen, R. H. B. lmerTest package: tests in linear mixed effects models. J. Stat. Softw. 82, 1–26 (2017).
R Core Team. R: A Language and Environment for Statistical Computing (R Foundation for Statistical Computing, 2015).
Wickham, H. et al. Welcome to the Tidyverse. J. Open Source Softw. 4, 1686 (2019).
Lüdecke, D. et al. sjPlot: Data visualization for statistics in social science. Zenodo https://doi.org/10.5281/zenodo.2400856 (2018).
Sun, Y. et al. The reliability and validity of PHQ-9 in patients with major depressive disorder in psychiatric hospital. BMC Psychiatry 20, 474 (2020).
Bhattacharjee, A. et al. Perfectly to a tee: understanding user perceptions of personalized LLM-enhanced narrative interventions. In Proc. 2025 ACM Designing Interactive Systems Conference 1387–1416 (ACM, 2025).
McGuire, A. P., Howard, B. A. N., Erickson, T. M. & Creech, S. K. Moral Elevation Online Intervention for Veterans Experiencing Distress Related to Posttraumatic Stress Disorder and Moral Injury (MOVED): pilot trial of a 4-week positive psychology web-based intervention. JMIR Form. Res. 7, e39894 (2023).
Huberty, J. L., Espel-Huynh, H. M., Neher, T. L. & Puzia, M. E. Testing the pragmatic effectiveness of a consumer-based mindfulness mobile app in the workplace: randomized controlled trial. JMIR MHealth UHealth 10, e38903 (2022).