Objective: To evaluate the efficacy of an adjuvant intervention based on a peer support program in the reduction of depressive symptomatology versus an online intervention in people with major depression in Primary Care Mental Health Units in Mallorca.

Design: Randomized clinical trial of two branches in a Mental Health Unit of Mallorca, where one branch will receive an adjuvant intervention based on a peer support program (Active Patient Program) and another branch (control) will receive information and exercises aimed at improving their mental health through the COGITO App, designed and validated for this purpose.

Scope and study subjects: The scope of the study will be the consultations of the Mental Health Unit (MHU) of Primary Care in Mallorca. The study subjects will be patients of these units who meet the criteria for Major Depression. The mental health professionals of the MHU will be in charge of recruiting participants who meet the inclusion and exclusion criteria. The required sample will be 70 subjects, 35 in each branch.

Variables: The main dependent variable is depressive symptomatology, measured through the Beck Depression Inventory (BDI-II). As secondary variables, quality of life and adherence to treatment will be included.

Data analysis: All analyses will be carried out using the SPSS statistical program. An intention-to-treat (ITT) analysis will be performed. The efficacy of the intervention (reduction of depressive symptoms (BDI-II)) will be assessed by a general linear model (ANOVA) at 6 weeks, 6 and 12 months, adjusted for baseline values.

Material and methods Type of study A two-branch randomized clinical trial will be conducted, in which one branch will receive the intervention based on a peer support program (Active Patient Program) and another branch will receive information and exercises aimed at improving their mental health through a validated App, free and in its Spanish version, called "COGITO", which consists of planning exercises based on cognitive-behavioral therapy. The App to be used can be found for free by accessing the following link: https://apps.apple.com/us/app/cogito-mct/id1557322291 (for Apple devices) https://play.google.com/store/apps/details?id=de.uke.cogitoapp\&hl=en\_US\&pli=1 (for Android devices).

Scope of the study The consultations of the Mental Health Unit (MHU) will be the site from which the subjects will be recruited. The MHU are outpatient and community facilities of the mental health network of the Balearic Islands, where people with mental health problems are followed up. They consist of a multidisciplinary team of psychiatry, psychology, mental health nursing and social work professionals. In addition to the administrative staff of these units.

Definition of study subjects The study subjects will be those persons suffering from Major Depressive Disorder and who are currently under follow-up with one of the professionals of the MHU.

Recruitment of participants Recruitment will be done through the medical records of each nurse, psychiatrist, psychologist or social worker of the USM with current follow-up and/or active diagnostic label of Major Depressive Disorder (according to ICD or DSM criteria) in the Primary Care Information System (e-SIAP).

An initial interview will be carried out by the research staff in collaboration with the health care staff of the reference MHU to verify compliance with the inclusion criteria for the study.

Justification of sample size Accepting an alpha risk of 0.05 and a beta risk of 0.2 in a bilateral contrast, 35 subjects in the intervention group (Active Patient) and 35 in the control group are required to detect a difference equal to or greater than 6 units in the Beck Depression Inventory (BDI-II). The common standard deviation is assumed to be 8. A loss-to-follow-up rate of 20% has been estimated (Castro LS et al. Psychiatry Res. 2013;210(3):906-12). Therefore, a total of 70 participants will be needed.

Primary and secondary variables. The primary dependent variable is depressive symptomatology measured by validated BDI-II.

The secondary dependent variables are quality of life and adherence to prescribed treatment. The main independent variable is the assigned group.

Other independent or control variables taken into account in this study are sociodemographic variables (age, gender, marital status, diagnostic label, year of diagnosis, educational level, pharmacological treatment, psychotherapy treatment, USM of reference, profession, comorbidities, current employment situation).

Description of the intervention

1. Recruitment and training of active patient trainers:

   Recruitment will be carried out by MHU professionals, through any device of the mental health network or through patients' associations and/or citizens' associations.

   The trainer patients must meet the following requirements according to the current protocol of the Active Patient Program, evaluated through the interview, the scales and questionnaires that the program stipulates in its action guide. All the information regarding this aspect can be found in detail at the following link: https://docusalut.com/handle/20.500.13003/18170.

2. Recruitment of participants The recruitment of the study subjects will be carried out by the multidisciplinary team of the MHU (psychiatrists, psychologists, nurses and/or social workers of each center). Once the sample has been recruited, an initial interview will be conducted by the staff of the Active Patient Program team to explain the procedure and assess whether the selected persons accept their participation and meet the inclusion criteria described above.

3. Randomization Once the necessary sample has been obtained, the participants will be randomized in a 1:1 ratio.Pseudo-anonymity of the data is guaranteed, since each participant will be identified with a numerical code that will not include any personal data.

4. Development of the intervention- Intervention group for patients benefiting from the Active Patient Program training.

   The training will consist of a workshop of 6 sessions of 2 hours each, following the model described in the protocol of the Active Patient Program but adapted to Major Depressive Disorder.

   The adaptation of this guide will be carried out by a group of professionals, from different disciplines, experts in mental health. Once the guide has been produced, it will be sent to people of reference in the field of depressive disorders at a national level, so that they can proceed to its revision.

   The sessions that will guide us in the preparation of the Major Depressive Disorder workshop are detailed in Annex I.- Control group through the COGITO App.The control group will receive a guideline of exercises guided through the COGITO App based on cognitive-behavioral therapy (CBT). The duration of the use of this App will be the same as the intervention of the Active Patient program (6 weeks), having to comply with a pattern of use of the App of 20 minutes daily in order to match the time dedicated to the intervention. Thanks to the design of the App, its use can be counted through the history of the exercises, as well as the appearance of warnings when the use is low.Daily reminders can also be activated to incentivize it.

5. Evaluation:

A pre-intervention evaluation will be carried out at the beginning of the intervention in both groups, another one at the end of the program sessions (6 weeks) and two post- evaluations at 6 and 12 months after completion.

The degree of depressive symptomatology, the quality of life and the degree of adherence to the prescribed treatment will be measured by means of valid instruments.

Selection and withdrawal of subjects

Inclusion criteria:

• People over 18 years of age.
• Attending consultations with any of the professionals in the USM mental health network.
• Having an active diagnostic label of Major Depressive Disorder, according to ICD or DSM criteria in the Primary Care e-SIAP program or meeting MINI TRAS criteria after individual interview for Major Depressive Episode.

Exclusion criteria

• People who present mental health disorders associated with a depressive disorder and who are in the acute phase of the disease.
• People who are not under active follow-up with any of the professionals of the USM.
• People with mobility problems and / or displacement to the health center.
• People suffering from another disease affecting the CNS (organic brain pathology or who have suffered a severe head injury, onset dementia or any other neurodegenerative disease, etc.).
• People with presence of uncontrolled serious medical, infectious or degenerative disease, which may interfere with affective symptomatology.
• People with significant risk of suicide according to medical criteria, assessed through follow-up interviews conducted by mental health professionals of reference.
• People with any medical, psychological and/or social problem that could seriously interfere with the patient's participation in the study.
• People who are legally incapacitated to make health decisions.

We randomized the participants across the informatic program named RedCap. Only was masking the outcome assessor.