Building EVA (Educación, Vinculación, y Autoayuda): Tutorial for the Development of a Digital Mental Health Chatbot...

Adolescents living with HIV face higher rates of mental health morbidity compared to other age groups, particularly depressive symptoms, while access to specialized services remains limited in many low- and middle-income countries. Chatbots offer a promising, low-cost approach to delivering structured mental health support in resource-constrained settings; however, practical guidance on how to develop such tools with end-user involvement remains scarce. This tutorial provides a step-by-step guide to the human-centered design and development of a mental health chatbot for adolescents living with HIV, illustrated through the creation of EVA (Educación, Vinculación, y Autoayuda), a chatbot cocreated with adolescents living with HIV in Peru. Guided by human-centered design principles, the tutorial covers three key steps: (1) understanding user needs through qualitative research, (2) iterative chatbot development with a Youth Advisory Board across five structured sessions, and (3) external review and testing before launch. Throughout the process, adolescents contributed to defining the chatbot's tone, visual identity, navigation structure, and content priorities. The chatbot was built using a low-cost messaging platform and incorporated multimedia components, including brief animated videos, to enhance engagement. Throughout development, iterative testing with the Youth Advisory Board and external health care professionals informed refinements in usability, content clarity, emotional tone, and accessibility. This tutorial synthesizes key methodological decisions, lessons learned, and challenges encountered, providing practical guidance for researchers and practitioners seeking to develop similar adolescent-centered digital mental health tools in low- and middle-income countries. Key takeaways include the importance of early and sustained adolescent involvement, the value of iterative prototyping, and the feasibility of building functional chatbots with limited resources to help address the health service gap experienced by adolescents living with HIV.