PsychogenX Library

Better Days: Research Library

The evidence base behind Better Days — an annotated bibliography of the research that informs its design.

Last reviewed: July 19, 2026 · Evidence reviewed through: July 19, 2026

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Better Days is an evidence-informed educational application designed to help people make better daily decisions, build sustainable habits, improve psychological well-being, and apply established psychological science to everyday life.

Rather than relying on a single psychological theory or therapeutic approach, Better Days draws from research across digital mental health, behavior change science, motivational psychology, emotion regulation, psychological flexibility, self-compassion, habit formation, implementation science, and positive psychology.

This Research Library presents a curated collection of foundational and contemporary sources that inform the design and development of Better Days. The selected literature emphasizes systematic reviews, meta-analyses, randomized controlled trials, professional frameworks, and landmark publications that are directly relevant to the app's educational purpose.

Annotated Bibliography

Thirteen sources spanning digital mental health, behavior change, motivation, emotion regulation, self-compassion, and habit formation.

Systematic review and meta-analysis

Linardon et al. (2024)

Linardon, J., et al. (2024). Current evidence on the efficacy of mental health smartphone apps: A systematic review and meta-analysis.

This review evaluates randomized controlled trials of smartphone-based mental health applications and concludes that digital interventions can produce meaningful, though generally modest, improvements in mental health outcomes. The authors also highlight substantial variation in app quality, study design, and user engagement.

Relevance to Better Days: Provides contemporary evidence supporting the use of smartphone-based psychological interventions while reinforcing the importance of evaluating each application on its own merits.

Systematic review and meta-analysis

Weisel et al. (2019)

Weisel, K. K., et al. (2019). Standalone smartphone apps for mental health: A systematic review and meta-analysis.

This review examines self-guided smartphone applications used without routine therapist support. Findings suggest that standalone digital interventions can benefit some users, although effectiveness varies considerably across interventions and populations.

Relevance to Better Days: Supports the educational self-guided model of Better Days while emphasizing realistic expectations regarding effectiveness.

Meta-analysis

Firth et al. (2017)

Firth, J., et al. (2017). The efficacy of smartphone-based mental health interventions for depressive symptoms: A meta-analysis of randomized controlled trials.

This study found that smartphone-based psychological interventions produced small-to-moderate reductions in depressive symptoms across randomized controlled trials while noting important differences between interventions and study quality.

Relevance to Better Days: Provides evidence that digital psychological interventions can be effective while underscoring the need for direct evaluation of individual applications.

Systematic review and meta-analysis

Torous et al. (2020)

Torous, J., et al. (2020). Dropout rates in clinical trials of smartphone apps for depressive symptoms: A systematic review and meta-analysis.

This review identifies user engagement and retention as major challenges for mental health applications and examines factors associated with continued participation.

Relevance to Better Days: Highlights the importance of designing features that encourage meaningful, sustained engagement.

Systematic review

Milne-Ives et al. (2023)

Milne-Ives, M., et al. (2023). Potential associations between behavior change techniques and engagement with mobile health apps: A systematic review.

This review evaluates how behavior-change techniques relate to user engagement in mobile health applications and concludes that no single technique consistently guarantees engagement.

Relevance to Better Days: Supports evidence-informed evaluation of reminders, goal tracking, notifications, and other engagement features.

Methodological framework

Nahum-Shani et al. (2017)

Nahum-Shani, I., et al. (2017). Just-in-time adaptive interventions (JITAIs) in mobile health.

This foundational paper introduces the Just-in-Time Adaptive Intervention (JITAI) framework for delivering personalized support when individuals are most likely to benefit.

Relevance to Better Days: Provides a scientific foundation for adaptive recommendations and context-sensitive guidance.

Meta-analysis

Weiss, Westerhof, & Bohlmeijer (2016)

Weiss, L. A., Westerhof, G. J., & Bohlmeijer, E. T. (2016). Can we increase psychological well-being? The effects of interventions on psychological well-being: A meta-analysis of randomized controlled trials.

This review examines interventions designed to improve psychological well-being and reports overall positive effects across multiple approaches.

Relevance to Better Days: Supports the app's emphasis on fostering positive psychological functioning rather than focusing solely on reducing distress.

Meta-analysis

Kirby, Tellegen, & Steindl (2017)

Kirby, J. N., Tellegen, C. L., & Steindl, S. R. (2017). A meta-analysis of compassion-based interventions.

This review synthesizes evidence showing that compassion-based interventions can improve several aspects of psychological functioning.

Relevance to Better Days: Supports designing experiences that encourage self-compassion, resilience, and recovery following setbacks.

Integrative review

Gollwitzer (1999)

Gollwitzer, P. M. (1999). Implementation intentions: Strong effects of simple plans.

This influential paper summarizes research demonstrating that “if–then” implementation plans help translate intentions into action by linking specific situations with planned responses.

Relevance to Better Days: Supports helping users create concrete, actionable plans rather than relying solely on motivation.

Prospective longitudinal study

Lally, van Jaarsveld, Potts, & Wardle (2010)

Lally, P., van Jaarsveld, C. H. M., Potts, H. W. W., & Wardle, J. (2010). How are habits formed: Modelling habit formation in the real world.

This study demonstrates that habit formation develops gradually through repeated behavior in consistent contexts and varies considerably across individuals and behaviors.

Relevance to Better Days: Supports encouraging consistency and persistence while avoiding unrealistic expectations about how quickly habits develop.

Foundational theoretical framework

Deci & Ryan (2000)

Deci, E. L., & Ryan, R. M. (2000). The “what” and “why” of goal pursuits: Human needs and the self-determination of behavior.

This landmark paper presents Self-Determination Theory, proposing that autonomy, competence, and relatedness are fundamental psychological needs that influence motivation and well-being.

Relevance to Better Days: Supports designing experiences that preserve user choice, encourage competence, and foster meaningful motivation.

Integrative review

Gross (2015)

Gross, J. J. (2015). Emotion regulation: Current status and future prospects.

This review summarizes contemporary research on emotion regulation and emphasizes that effective strategies depend on context rather than universal rules.

Relevance to Better Days: Supports teaching flexible approaches to understanding and responding to emotions.

Framework-development paper

Michie, van Stralen, & West (2011)

Michie, S., van Stralen, M. M., & West, R. (2011). The behaviour change wheel: A new method for characterising and designing behaviour change interventions.

This paper introduces the Behaviour Change Wheel and COM-B model, providing a systematic framework for understanding and influencing behavior.

Relevance to Better Days: Supports designing educational features that account for users' capability, opportunity, and motivation when pursuing behavior change.

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