PROJECT SUMMARY/ABSTRACT COVID-19 and upticks in U.S. racialized violence are stealing our collective breaths and brewing a potent mix, or syndemic of stress, trauma, and negative affect – key risk factors for behavioral health disparities. Behavioral health disparities among Black males are well-documented and known to erupt during young adulthood (ages 18-29) when this population exhibits steep escalations in problematic substance use (e.g., marijuana and alcohol). Many young adult Black males also reside in disadvantaged neighborhoods settings with conditions like high violence, alcohol, and other drug activity linked to substance use. While we know that Black males residing in disadvantaged neighborhoods are disproportionately impacted by racism (i.e., racial profiling by police and citizens) and that racism is a risk for self-medicating with alcohol and marijuana, few substance use interventions have been adapted to target this culturally-relevant stressor or related trauma symptoms. Mindfulness-based stress reduction (MBSR) interventions featuring meditation and breathing space training have been shown to reduce maladaptive stress response, trauma symptoms, and substance use, principally by improving self-regulation (i.e., affect and physiological). Yet, a fundamental lag exists in the cultural adaptation of established MBSR interventions and exploration of new modalities for delivering them to Black males. As a result, less is known about their feasibility, acceptability, or probable effectiveness in this disparity population. Successful MBSR interventions require participant home practice and deployment of acquired skills in real-world settings. Integrating mobile technologies, especially ones providing ‘real-time’ feedback, could further enhance MBSR interventions’ impacts on substance use mitigation among young adult Black males by providing supportive nudges in moments and settings when racism-related stress and trauma symptoms likely peak. Adapted, mobile technology-assisted MBSR interventions will likely be more acceptable by young adult Black males when they are developed with their input and address culturally relevant stress, trauma, and the gender norms (e.g., boys don’t cry) often encouraging males to regulate negative affect by pushing it out of conscious awareness. Our theory-driven central hypothesis, is that preventive interventions aimed at modulating racism-related stress response, trauma symptoms, and affect regulation especially in ‘real-time’ will reduce problematic substance use progression among young adult Black males. This R34 application proposes the following aims to be carried out among 18-29 year-old Black males in Durham, NC and Hartford, CT – settings with strikingly similar neighborhood disadvantage: 1) To culturally adapt a validated instructor-led, group-based and mobile technology-assisted, MBSR intervention; 2) To pilot test and assess the feasibility/acceptability of a culturally adapted instructor-led, ...