Effect of digital intervention in the self-management of depressive symptoms: the MENTINA trial - a study protocol for a randomised controlled parallel-group trial.

introductionDepression and sub-diagnostic depressive syndromes are prevalent and associated with suffering and reduced life expectancy. Access to care is limited even in countries with developed healthcare systems. In this context, it is important to strengthen the self-management expertise of people suffering from depressive symptoms. Smartphones offer the possibilities for improved self-management based on long-term monitoring of symptoms.The present multicentre randomised controlled trial (the Protecting mental health in times of change (MENTINA) trial) aims to evaluate whether (1) daily smartphone-based monitoring and automatic rule-based feedback+smartphone-based outcome evaluations versus (2) smartphone-based outcome evaluations alone will improve depressive symptoms and other clinically relevant outcomes in participants with current depressive symptoms and/or one or more prior depressive episodes during a 12-month trial period. METHODS AND ANALYSIS: The MENTINA trial is a multicentre randomised controlled parallel-group trial conducted in Denmark, Germany and Spain. Participants with current depressive symptoms and/or one or more previous depressive episodes are invited to participate. The included participants will be randomised to (1) daily smartphone-based monitoring and automatic rule-based feedback+outcome evaluations via smartphone (intervention group) or (2) outcome evaluations via smartphone alone (control group). All participants can continue with ongoing treatment in case they receive it. The trial started in May 2025 and has currently included 115 participants. The outcomes are differences between the intervention group and the control group in (1) Patient Health Questionnaire 9-items (PHQ-9) measured every 14th day during the 12-month trial period (primary), (2) WHO Quality of Life-BREF, Generalised Anxiety Disorder-7, monthly change in PHQ-9, proportion of participants with ≥50% reduction in PHQ-9, remission rate defined as PHQ-9≤9 and ≥5-point improvement, PHQ-9 scores after 6 months, area under the curve for PHQ-9 over the 12 months trial period, subgroup analyses in PHQ-9 in participants with or without lifetime depression, Perceived Stress Scale, user-reported healthcare contacts, usability of the app and negative effects, number of depressive episodes+duration and depressive-free days based on PHQ-9. A total of 660 participants will be included in the MENTINA trial. ETHICS AND DISSEMINATION: The MENTINA trial is funded by the European Union under Grant Agreement No. 101 080 651. Ethical approval and approval from Medical Agencies have been obtained from Denmark (CIV-25-02-051094), Germany (CIV-25-02-05109) and Spain (CIV-25-02-051094). The results will be published in peer-reviewed academic journals, presented at scientific meetings and disseminated to patients' organisations and media outlets. TRIAL REGISTRATION NUMBER: NCT06919133. PROTOCOL VERSION: Version 6, January 2026.