RegulEm, an unified protocol based-app for the treatment of emotional disorders: a parallel mixed methods usability and quality study.

Background: Interest in mental health smartphone applications has grown in recent years. Despite their effectiveness and advantages, special attention needs to be paid to two aspects to ensure app engagement: to include patients and professionals in their design and to guarantee their usability. The aim of this study was to analyse the perceived usability and quality of the preliminary version of RegulEm, an app based in the Unified Protocol, as part of the second stage of the app development.

Methods: A parallel mixed methods study was used with 7 professionals and 4 users who were previously involved in the first stage of the development of the app. MARS, uMARS and SUS scales were used, and two focus groups were conducted. Descriptive statistical analysis and a thematic content analysis were performed in order to gather as much information as possible on RegulEm's usability and quality as well as suggestions for improvement.

Results: RegulEm's usability was perceived through the SUS scale scores as good by users (75 points) and excellent by professionals (84.64 points), while its quality was perceived through the uMARS and MARS scales as good by both groups, with 4 and 4.14 points out of 5. Different areas regarding RegulEm's usability and suggestions for improvement were identified in both focus groups and 20% of the suggestions proposed were implemented in the refined version of RegulEm.

Conclusion: RegulEm's usability and quality were perceived as good by users and professionals and different identified areas have contributed to its refinement. This study provides a more complete picture of RegulEm's usability and quality prior analysing its effectiveness, implementation and cost-effectiveness in Spanish public mental health units.