The Role of Digital Therapeutic Alliance in Mental Health Outcomes: Secondary Analysis of a Randomized Controlled Trial

Digital therapeutic alliance (DTA), as suggested by the latest empirical evidence, influences engagement and outcomes in digital mental health apps. However, little is known about whether DTA plays a role in moderating mental health outcomes in fully automated apps. The present study examined whether DTA moderates changes in perceived stress, anxiety, and depressive symptoms during the use of ReApp, a fully automated mental health app aiming to enhance positive cognitive reappraisal (PCR). Ninety-two young adults used ReApp for three weeks and completed questionnaires before and after the intervention. DTA was measured at follow-up with the mobile Agnew Relationship Measure (mARM-G). Linear mixed-effects models were used to test whether general DTA and its five subscales (bond, partnership, confidence, openness, and client initiative) moderated mental health outcomes. The results showed a significant main effect of the openness subscale on perceived stress (β = −2.12, p = .04), although openness did not function as a moderator. Similarly, none remaining mARM-G subscales showed moderation effects, and general DTA did not moderate changes in mental health outcomes. These findings suggest that the mechanism through which users develop a sense of alliance with mental health apps may differ from alliance processes in traditional therapy. Given these conceptual differences, measures adapted from therapist-based frameworks, including the mARM-G, may not adequately capture DTA or its digital-specific processes. Future research should use newly developed alliance measures designed specifically for digital tools to more accurately assess the role of DTA in automated mental health apps.