PROJECT SUMMARY / ABSTRACT On a population level, digital mental health interventions effectively reduce depression and anxiety symptoms. However, middle-aged and older adults with depression and/or anxiety and coexisting chronic pain have not been adequately represented in digital mental health studies and are a significant population because: 1) chronic pain reduces the effectiveness of stand-alone mental health treatment unless a person’s pain is simultaneously addressed; 2) the prevalence of chronic pain increases with age; 3) physical and mental health related disability in these age groups have unique downstream effects (lost workforce, effects on dependent children, strain on caregiver availability); and 4) use of technology in these age groups is widespread and growing, but these users have unique digital health needs and preferences. This proposal is a partnership between Washington University and Wysa, an established mental health app company that delivers cognitive behavioral therapy, mindfulness training, and sleep tools using chatbot technology and human coaches. Wysa has developed an app specifically for people with mental illness and coexisting chronic pain (Wysa for Chronic Pain (WCP)) which addresses depression and anxiety via the intermediate mechanisms of behavioral activation, pain acceptance, and sleep quality. However, the app is not yet designed to meet the usability needs of middle-aged and older adults with chronic pain. The goals of this proposal are to: 1) refine an established digital mental health intervention (WCP) for middle-aged and older adults with depression and/or anxiety and coexisting chronic pain, and 2) determine its effectiveness. The central hypothesis is that incorporating just-in-time adaptive interventions (JITAIs) and other usability-related adaptations will improve app engagement and, subsequently, depression and anxiety symptoms in this target population. Using a human-centered design approach, the Behavioral Intervention Technology (BIT) model will be leveraged to link established behavioral change theory with technology-related usability and engagement factors. Study activities will follow the Discover, Design / Build, and Test (DDBT) framework. Aim 1 is to identify stakeholder- informed contextual determinants of engagement with WCP by the target population. Members of the target population with varying levels of technological literacy will participate in semi-structured interviews and usability testing. Next, in a series of micro-randomized trials, adaptations designed to increase engagement with WCP (e.g., JITAIs) will be created, tested, and iteratively refined (Aim 2). Finally, in a pragmatic randomized clinical trial including 4,000 commercial Wysa users, the real-world effectiveness of the package of adaptations to improve depression and anxiety symptoms within 12 weeks will be determined in a hybrid type 1 effectiveness- implementation study (Aim 3). This proposal responds to PAR-22-154’s ...