JMIR Publications

ABSTRACT

Background:

Digital mental health tools (DMHTs) offer scalable support, but engagement varies. Understanding what shapes initiation and ongoing use is essential for effective design and implementation.

Objective:

To synthesise determinants of adults’ initiation and engagement with DMHTs, organised through two lenses: (a) psychological factors aligned with the Theory of Planned Behavior (TPB) and (b) design and access features.

Methods:

A systematic search of nine databases (June 2025) identified qualitative and mixed-methods primary studies reporting end-users’ experiences with DMHTs. Studies were screened and reported in accordance with PRISMA. Quality appraisal used QuADS. Data were synthesised using a framework-guided thematic approach, mapping findings to TPB constructs and complementary design/access domains.

Results:

22 studies met inclusion criteria. Findings clustered into two interdependent domains. TPB constructs explained how beliefs, social expectations, and perceived control shaped decisions to start and persist with DMHTs. Design and access features frequently acted through these same pathways, especially by altering perceived behavioral control, with cost, connectivity, device constraints, and time flexibility affecting feasibility, with content design and privacy shaping perceived value and trust. Perceived fit (goals, cultural/linguistic relevance, and routine alignment) consistently influenced both initiation and continuation. Several features operated bidirectionally, depending on context, the same feature could facilitate or hinder engagement.

Conclusions:

Engagement with DMHTs is jointly determined by users’ beliefs and the design and access conditions within which tools are offered. Implementation should pursue a dual strategy, strengthen willingness to seek support (addressing attitudes, norms, and perceived control) while engineering low-effort, trustworthy, and context-appropriate experiences. Priorities include equity-focused policies (data costs, devices, connectivity), transparent data practices, co-design with diverse communities, and consistent, theory-informed outcome measures.