Emotional disorders (ED) are one of the leading causes of disability. They are highly prevalent and have an impact on quality of life. Addressing them places an overload on the National Health System (NHS), generating waiting lists and limiting appropriate care. The need for cost-effective solutions has led to the consideration of the transdiagnostic approach and the use of digital solutions. Both perspectives have demonstrated efficacy in a large number of randomized clinical trials. As a result, investment in digital health interventions is on the rise to improve access to care in overburdened healthcare systems. However, their integration and implementation in health systems remains limited. Implementation Science emerges to facilitate the integration of interventions into clinical practice through specific strategies that overcome barriers and optimize their sustainability. The objective of this project is to examine the effectiveness, economic costs and feasibility of implementing an online psychological treatment program for emotional disorders in mental health services. The Mutua and UJI teams have already carried out the transfer of the online program. In order to facilitate the adoption and sustainability of this program and that it can be used by mental health professionals in daily practice, a hybrid design 1 study will be carried out in which not only the efficacy but also the possibility of adoption and the analysis of economic costs in comparison with the usual treatment will be evaluated.

The World Health Organization (WHO) defines mental health as "a state of well-being in which every individual realizes his or her potential, can cope with the stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community." Many people do not achieve this state of well-being, or even if they do, they lose it at some point in their lives. When this happens, it can take the form of a mental disorder, the most prevalent being depressive and anxiety disorders, which affect around 6% of the population in Spain, causing a major impact on their social, work, and personal lives. In the wake of the COVID pandemic, there has been greater awareness in society of the importance of mental health.

However, despite this and despite the availability of effective pharmacological and psychological treatments that can significantly alleviate the symptoms of many mental disorders, health systems are not responding adequately to people with mental disorders. A study exploring mental health care in 84 countries, including Spain (Moitra et al., 2022), found that only 23% of people with depression in high-income countries and 3% in middle-income countries received minimally adequate treatment for their problem. This indicates that the problem goes beyond a health issue; it is a social and ethical problem, since without adequate treatment, many mental disorders have very negative consequences that significantly reduce well-being, satisfaction, and quality of life and cause social inequalities.

Possible solutions include increasing the number of professionals and organizing the provision of services more efficiently, from prevention to specialized care, including primary care. In this regard, there is a very solid line of research that has shown that online psychological treatments are as effective as face-to-face treatments for people with moderate depression and anxiety disorders. This project is part of the objective of optimizing mental health services by incorporating an online treatment program in order to increase citizens' access to effective psychological treatments.

The researchers involved in this application form a team that combines healthcare work with scientific work in order to implement an online transdiagnostic treatment program, going beyond individual face-to-face therapy, increasing diversity in the ways psychotherapy is administered, being flexible, and expanding the range of services offered. The team at the Universitat Jaume I (UJI) has developed and validated the "UJI online transdiagnostic protocol" in rigorous clinical trials and with the collaboration of affected individuals (user-centered design), which is effective in the short and long term for depression and anxiety. Over the past year, the UJI team and the Mutua Terrassa team, through a transfer agreement, have integrated the program into Mutua's technology platform. This application aims to promote the adoption and sustainability of this program as an additional alternative available to mental health professionals at the two mental health centers run by Mutua Terrassa, which serve a population of more than 200,000 inhabitants.

The idea is to offer this program to people with moderate depression and/or anxiety so that professionals can intensify face-to-face care for other patients with more serious conditions. A clinical trial will be conducted to compare the effectiveness and costs of the online program with the usual treatment received by patients. In addition, the opinions of professionals and patients about the program will be evaluated, and the barriers and facilitators of incorporating the online program into services will be analyzed. The results will indicate the usefulness of this alternative. If the results are positive, an affordable, evidence-based alternative will be available that will increase the scope and scalability of treatments, which will be more integrated into people's daily lives, expanding the settings in which interventions are provided, with the acceptance of those involved. The project's actions include a plan to disseminate the results to society through social media networks belonging to both the UJI and Mutua; the organization of a specific conference on the project's results for primary care and specialist professionals at Mutua and another conference for patient and user associations; and holding meetings with managers who can make decisions about the sustainability of the program and its adoption in other services (General Directorate of Mental Health of the Valencian Community, management, health, and executive boards of Catsalut).

Patient Inclusion Criteria:

• Over 18 years of age.
• Meet the diagnostic criteria for an anxiety or depressive disorder according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).
• Understand and read Spanish or Catalan.
• Have access to the Internet and an email address
• Give informed consent.

Patient Exclusion Criteria:

• Diagnosis of schizophrenia, bipolar disorder, or alcohol or substance dependence.
• High risk of suicide.
• Presence of a medical condition that prevents psychological treatment.
• Receiving other psychological treatment (other than TAU or the online program) during the study.
• For participants in the online treatment condition with pharmacological treatment, this must be stabilized (doses cannot be changed or increased during the study, only reduced).

Inclusion Criteria for mental health Professionals:

• They work at centers participating in the study.
• They agree to participate in the study.
• They sign an informed consent form.