Project Summary Veterans with elevated anxiety sensitivity are likely to suffer disproportionately and unnecessarily following the COVID-19 pandemic. Beyond the emotional suffering, this will likely manifest in functional impairment. Addressing this potential crisis requires dissemination of interventions targeting risk factors that maintain anxiety and functional impairment without overloading an already taxed mental health services pipeline. Anxiety sensitivity, or fear of anxiety sensations, is a transdiagnostic risk factor that exacerbates anxiety, results in functional impairment, and increases the strength of the relation between anxiety and functional impairment. Thus, anxiety sensitivity is an ideal target to restore functioning in Veterans with reporting functional impairment. Preliminary data by our group has demonstrated that functional impairment due to COVID-19 is common, enduring, and is predicted by levels of anxiety sensitivity, suggesting a critical need to intervene. Further, there is robust evidence that anxiety sensitivity is malleable using cognitive-behavioral therapy techniques, even when delivered in brief, one-session interventions. Our group has shown brief one- session interventions are efficacious and rated as acceptable by participants. The increased use of telehealth and mobile apps in the Veterans Healthcare Administration provides an opportunity for this brief evidence- based intervention to be disseminated broadly. The proposed study will be the first to adapt and test Brief Enhanced Anxiety Sensitivity Treatment (BEAST) for functional impairment in Veterans with elevated anxiety sensitivity. BEAST comprises a one-session intervention including psychoeducation about the nature of anxiety, identification and challenging of common maladaptive thoughts about anxiety sensations, and interoceptive exposure to demonstrate the benign nature of anxiety. BEAST also includes a two-week ecological momentary intervention component designed to provide ecologically valid opportunities to practice the skills acquired during the one session. The proposed aims in this pilot feasibility and acceptability trial are to 1) adapt BEAST to be delivered via telehealth and a mobile app working with stakeholders and the Center for Mobile Applications Research Resources & Services and 2) pilot test the intervention for acceptability and feasibility. This application is directly responsive to RR&D Small Projects in Rehabilitation Research (SPiRE) RFA RX-22-003. We target functional impairment in Veterans with elevated anxiety sensitivity, a common finding in people with anxiety disorders. Findings from this pilot trial will provide the necessary demonstration of acceptability, feasibility, and usability of BEAST and its constituent components. This will allow us to expeditiously conduct a fully powered randomized control trial to demonstrate efficacy of BEAST and then a dissemination trial. Disseminating a brief anxiety sensitivity intervent...