Project Summary/Abstract Sexual minority women (SMW) are one of the highest-risk groups for posttraumatic stress disorder (PTSD), hazardous drinking (HD), and comorbid PTSD and HD (PTSD-HD); disparities are heightened for those with multiple minoritized identities. These disparities are rooted in SMW’s disproportionate and cumulative exposure to sexual identity-specific and intersectional forms of stigma, trauma, and lack of safety. The self-medication model posits that alcohol is often used to reduce distressing PTSD symptoms. Yet, few studies have tested the temporal precedence of PTSD in HD development and maintenance, especially in SMW. Sensitization to repeated psychosocial stressors may lower SMW’s threshold for tolerating distress, leading to persistent stress reactivity and PTSD-HD risk. Single-session interventions (SSIs) with cognitive restructuring and exposure components hold promise for addressing mechanisms (e.g., emotion regulation) underlying PTSD-HD and broadening access to low-intensity treatments among SMW. The proposed research is within the scope of the parent award, directly responds to NOT-OD-24-032, and advances addiction science by clarifying the long- term effects of PTSD on HD, identifying biopsychosocial drivers of PTSD-HD, and guiding the initial adaption of an SSI targeting cognitive reappraisal to mitigate stress reactivity, PTSD symptoms, and alcohol craving among SMW. Specific aims are to: (1) examine prospective longitudinal associations between PTSD symptom severity and cluster and HD among 515 SMW and determining for whom severe PTSD symptoms and specific PTSD clusters may be linked to elevated HD levels 10 years later; (2) explore whether intersectional stigma cues induce stress reactivity and assess variability in state PTSD symptom severity and alcohol craving in response to intersectional stigma-related reactivity among 75 SMW; and (3) conduct formative interviews with 30 SMW and 5 Community Advisory Board members from Aim 2 about the acceptability, feasibility, and improvement of an affirmative SSI focused on cognitive reappraisal and tailored to address personalized stress cues for SMW with PTSD-HD. Findings will inform a future planned R01 to assess stress reactivity to stimulus- specific cues, examine variations in state PTSD symptoms and alcohol craving based on stimulus-specific stress reactivity, and formally adapt and pilot test a cognitive reappraisal-focused SSI representing the first brief treatment providing potent, accessible strategies for reducing PTSD-HD in the context of salient cue exposure among SMW. The timeliness of this supplement is supported by critical research gaps highlighted in the proposal, federal funding priorities, and the