PROJECT SUMMARY/ABSTRACT This career development award will provide didactic and experiential training and mentorship necessary for the candidate to become an independent and fully-funded health services researcher focused on the development and testing of health-oriented emergency department strategies to improve primary and secondary prevention of substance use disorders (SUD). The research plan focuses specifically on the epidemic of opioid use disorder (OUD), fueled by incident OUD which has been largely iatrogenic (i.e., prescribed opioids leading to OUD despite being used as directed for therapeutic purposes). Guidelines and legislation have targeted provider prescribing, but the role of the patients in therapeutic decision-making has not been addressed directly. There is an urgent and imperative need to understand factors influencing patients' motivation to seek and/or use opioids and engage them as stakeholders in the balance of pain and OUD risk. Emergency departments (EDs) have been a prime subject of opioid prescribing interventions, because they frequently initiate or continue therapeutic opioids and do so in circumstances with little provider-patient familiarity or follow-up care. The objective of this study is to measure and model associations between ED patient decision-making factors (knowledge, attitudes, beliefs, and perceptions) and patient motivation to use opioids for pain relief or avoid OUD risk. The central hypothesis is that ED patients' desire for therapeutic opioids and decision to use them when available results from potentially modifiable cognitive factors. We will conduct a mixed-methods study using a combination of focus groups, cross-sectional quantitative survey, and longitudinal follow-up of opioid seeking and therapeutic use after ED visit for acute pain to accomplish the following aims: 1) Establish a qualitative understanding of cognitive factors influencing patient motivation to use opioids for acute pain; 2) Develop the Decisions To use Opioids (DTO) survey instrument to quantify potential cognitive determinants of patient motivation to use opioids for acute pain; including 2a) Psychometric testing of the DTO, and 2b) Measure the contribution of cognitive factors to patient motivation to seek/use opioids. This will promote highly impactful advances in the field of iatrogenic OUD, by informing shared decision- making models and new behavioral interventions. The research plan is also highly complementary to the career development of an independent clinical researcher focused on the development of primary and secondary SUD prevention strategies in the ED setting, providing experience in mixed-methods, longitudinal prospective clinical research, survey validation, and predictive modeling, as well as rich preliminary data to support future investigation under the direction of a highly qualified and multidisciplinary team of mentors. The quintessential contribution of this research will be to engage the patient in...