Improving Digital Mental Health Interventions: ENGAGEment as Mechanism of Impact

Project Information

ENGAGE

Grant agreement ID: 101078533

DOI

10.3030/101078533

EC signature date 26 February 2023

Start date 1 June 2023

End date 31 May 2028

Funded under

• European Research Council (ERC)

Total cost

€ 1 499 590,00

EU contribution

€ 1 499 590,00

Coordinated by

UNIVERSITEIT TWENTE
Netherlands

Periodic Reporting for period 1 - ENGAGE (Improving Digital Mental Health Interventions: ENGAGEment as Mechanism of Impact)

Reporting period: 2023-06-01 to 2025-11-30

Summary of the context and overall objectives of the project

Millions of people struggle with mental health issues, such as depression and anxiety. Effective treatments exist but are not within reach of everyone due to limited resources. Digital Mental Health Interventions (DMHIs), in which treatments are delivered by using technology via the Internet and apps, can be a solution. However, high rates of drop-out and large individual differences in outcomes make them not yet an adequate solution. Due to scarce process research, with a largely mono-disciplinary focus and reliance on group-level studies, we have limited insight into how to match DMHI components to individuals.

In ENGAGE, I tackle these issues by proposing that engagement is the mechanism of impact that provides the missing link between the intervention components and individual outcomes. Earlier research has shown that engagement is a multidimensional and interdisciplinary concept consisting of behaviour, cognition, and affect. I have developed a first scale to measure engagement, shown individual differences and have shown individual engagement is predictive of outcomes. However, the developed scale is a rudimentary way of measuring engagement using self-report at fixed time-points and as a one-dimensional construct. Consequently, we have only a basic understanding of engagement which does not do justice to its complex multidimensional nature.

ENGAGE will yield the following insights and outcomes:
- A fine-grained understanding and measurement of real-time engagement, showing the relationship between the dimensions, both on an individual level and over time (WP1).
- Expanding the toolbox of intervention designers to directly influence the individual mechanism of impact, by identifying and analysing the effect of strategies which influence individual engagement with DMHIs (WP2).
- Verification of engagement as mechanism of impact within DMHIs, by studying the relationship between intervention components, engagement, and outcomes within personalised and adaptive DMHIs (WP3).

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

WP1: Real-Time Engagement
Achievement 1: Optimized Conceptualization of Engagement
We applied theory triangulation to reconceptualize engagement with DHIs, synthesizing Postphenomenology, Social Practice Theory, and Social Cognitive Theory into the Dynamic EngagEment Process framework for DHIs (DEEP-DHI). This framework views engagement as a dynamic, context-dependent process shaped by individual, environmental, and material factors. It moves beyond static, usage-based definitions and supports design and evaluation grounded in lived experience. Manuscript under review.

Achievement 2: Engagement Measurement—A Review of Reviews
This review synthesizes how engagement with DHIs is measured. Twenty-four reviews were included, with measures categorized as subjective (e.g. TWEETS, SUS, interviews) or objective (e.g. app use, session duration, feature use, tracking data). Conceptual clarity across studies is lacking; many definitions are inconsistent, highlighting a need for alignment between conceptualizations and measures. Manuscript in preparation.

Achievement 3: Longitudinal Engagement Experience—EMA Study
Using qualitative methods, this study explored how engagement dimensions shift over time in eight self-identified engaged DMHI users. Data included interviews, think-aloud sessions, and repeated open-ended EMA questions. Preliminary results show fluctuating BCA engagement. Notably, low behavioral use sometimes co-occurred with cognitive or affective engagement. Findings reinforce that engagement is dynamic and influenced by routines, goals, and context. Manuscript in preparation.

WP2: Strategies for Individual Engagement
Achievement 4: Scoping Review on Engagement Strategies
The review mapped strategies used across DHIs and examined design and measurement approaches; 14 papers formed the preliminary synthesis. Common strategies included gamification, reminders, and digital prompts. Frameworks used included persuasive system design, behavior change taxonomy, and gamification. Engagement was often measured behaviorally, but inconsistently reported. Findings reveal a fragmented landscape and emphasize the need for clearer, more tailored strategies. Manuscript in preparation.

Achievement 5: Design Perspectives on Engagement
Thirteen interviews with multidisciplinary DHI developers revealed four themes: (1) varied definitions of engagement, (2) strategies like digital coaches and simplicity, (3) reliance on frameworks (e.g. co-design, persuasive design), and (4) challenges in tailoring and sustaining engagement. Developers underscored the central yet often overlooked role of engagement in DHI design. Manuscript in preparation.

WP3: Verify Engagement as a Mechanism of Impact
Achievement 6: Engagement Patterns as Predictors of Outcomes
Secondary analysis of data of a factorial trial showed that engagement trajectories (e.g. increasing or recovering engagement) predicted better outcomes than early engagement alone. Sustained or improving engagement over time led to more positive effects, underscoring engagement as a dynamic mechanism of impact. Manuscript in preparation.

Achievement 7: Personalization, Choice, and Adaptiveness Study
In a two-week mixed-methods study, 34 students were assigned to either a engagement-based or symptom-based DMHI. Engagement, satisfaction, and effectiveness were assessed through questionnaires and interviews. While no significant differences were found in outcomes, students in the engagement group and those who didn’t switch reported higher satisfaction and engagement. Interviews emphasized the value of autonomy and adapting to a better-fit DMHI. Manuscript in preparation.

Achievement 8: Implementing Engagement—A Social Practice Perspective
This viewpoint study applied Social Practice Theory to digital health use. Using cases like EHRs and self-tracking, we argue that engagement and implementation should be seen as embedded in broader health practices, not isolated behaviors. We call for shifting research focus from promoting “use” to fostering sustainable digital health practices and integrating interdisciplinary perspectives. Manuscript under review.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Achievement 1 was unplanned, but a necessary step in grounding the concept of engagement better in theory. I would consider this as advancing the research field significantly, as the framework conceptualizes engagement on relational, individual, and social levels, going beyond the current “engagement as usage” views. Moreover, the framework’s theoretical foundation provides a needed addition to the mostly empirical discussions surrounding engagement.

Achievement 6 was a planned step, but it considerably advances the research field as it shows the temporal relation of engagement with outcomes. This relation is often posited but not empirically shown. By showing this, it provides the first evidence that engagement is the mechanism of impact that is the foundation of the current ERC project.

Illustration of the project