PROJECT SUMMARY/ABSTRACT Young adults (18-30 years) in the US are suffering from unprecedented increases in depressive symptomatology, anxiety, and loneliness, which are major risk factors for mental illness. Building from our controlled clinical trials of digital mindfulness meditation training, our company has released an interactive and data-driven mindfulness meditation application called Equa, which can help reduce the mental distress and loneliness facing young adults today. There are now 1000s of mindfulness meditation digital apps on the commercial market, but these apps suffer from poor user engagement over time, and our clinical trials show that sustained engagement is critical for mental health outcomes. Our overarching goal is to translate our clinical trials results and evidence-based Equa training platform into a commercial product that helps young adult users stay engaged with mindfulness training in order to reduce mental distress and loneliness. This proposal describes new research and development of a respiration biosignal feedback technology, which will help Equa users better visualize and understand their mindfulness skill development. Building on our preliminary studies, this fast track SBIR proposal will first validate a new respiration biosignal feedback tool on Equa in distressed young adults (in Phase I), and then to test whether this new Equa biosignal feedback improves user engagement and outcomes among distressed young adults (in Phase II). Specifically in Phase I, we will collect Equa-guided meditation data with respiration tracking in distressed young adults (Study 1 N=80) in order to optimize deep learning algorithms that link changes in respiration dynamics with pre-post session changes in mindfulness skills (Phase I performance milestone: 90% prediction accuracy). We will also conduct usability testing (Study 2 N=60) with the respiration biosignal feedback features on Equa (Phase I milestones: >85 on System Usability Scale (SUS), and experimentally evaluate if Equa-augmented respiration biosignal tracking significantly increases user satisfaction relative to Equa with no biosignal tracking). In Phase II, we will conduct a three arm clinical trial comparing Equa guided meditation training with respiration biosignal feedback to Equa without respiration biosignal feedback or an active stress management control program in distressed young adults (N=300). It is predicted that respiration biosignal feedback (relative to the two active comparator groups) significantly increases user satisfaction and platform engagement, and significantly reduces mental distress and loneliness at post treatment and one month follow-up. In doing so, this research will position Equa for dissemination to a large young adult market. The ultimate goal of this fast track proposal is to develop a more engaging and evidence-based mindfulness meditation product for curbing the growing mental health crisis in young adults.