ABSTRACT The proposed K99/R00 award aims to guide the applicant to research independence, specifically in mobile health (mHealth) interventions for emerging adults with alcohol misuse and comorbid conditions. Emerging adults have the highest rates of alcohol use disorders, suicidal ideation, and suicide attempts compared to any other age group. These problems are highly comorbid, with alcohol intoxication serving as a risk factor for suicidality. However, utilization of outpatient treatment services for alcohol or mental health is extremely low in this population, even following emergency department (ED) visits for either problem. Emerging adults are likely to be responsive to mHealth interventions, and mHealth is well-suited to the ED. mHealth can address an urgent public health need by bridging the gap between discharge and access to outpatient care and by supporting emerging adults who do not access outpatient care. This study seeks to design an evidence-informed interactive, avatar-guided mHealth intervention to provide ongoing education, skills practice, mood and behavior monitoring, and personalized feedback to reduce alcohol misuse and suicidality. This mHealth platform will be developed based on a review of commercial suicidality and alcohol mHealth apps, in-person integrated interventions, and an existing avatar-based mHealth platform, developed by co-mentor Easton. The study aims to: 1) seek feedback on the proposed mHealth intervention avatar, content, and features from a national youth advisory board, consumers (e.g., emerging adults with alcohol misuse and suicidality; n=25), clinical experts in emerging adult alcohol and suicidality treatment (n=10) and ED staff (n=10) creating an alpha version of the intervention; 2) test [usability] of the alpha version and [feasibility of research protocols] in an open pilot trial with (n=20) emerging adults, to inform a beta version, and 3) evaluate [acceptability and feasibility] in a randomized controlled [feasibility] trial comparing the beta version [of the avatar-guided mHealth intervention + standard ED care; n=30)] to an active control, a commercial suicide prevention app (MY3 [+ standard ED care; n=30). Secondary aims of the RCT are to test for safety and early signals of efficacy on a range of alcohol, suicidal ideation, and outpatient care variables at 6-, 12-, and 24-weeks post-randomization.] An exploratory aim is to examine within-person changes in same-day alcohol misuse and SI severity between intervention groups via daily diary and ecological momentary assessment. The training and career development plan includes courses, workshops, seminars, reading, and hands-on research in areas critical to the PI’s independence: mHealth intervention development within interdisciplinary teams, integrated alcohol and suicidality interventions for emerging adults, randomized controlled trials with fully-technology-based interventions, and lagged sequential analysis with ecological data. The R00 ...