Project Summary Identifying context specific risks for individuals who inject heroin is central to overdose prevention and the control of infectious diseases, given that the current opioid crisis is now characterized by a heroin supply contaminated with synthetic opioids. While epidemiological patterns of risk are known from previous studies of heroin use, what is not clear is how individual behaviors, strategies and local social and situational factors in the current synthetic opioid/non-pharmaceutical fentanyl (NPF) crisis are promoting risk factors and/or self-protective behaviors in distinct emerging fentanyl “hot spots”, such as Ohio. Informed by the Drug, Set, and Setting Framework with concepts from the Symbiotic Model of Risk Reduction, this application will determine how social and environmental determinants influence the relationship between heroin/NPF use trajectories, adverse health outcomes, and risk or self-protective behaviors among individuals who inject heroin/NPF in Dayton, Ohio. Using adaptive respondent driven sampling, 60 individuals reporting injecting heroin/NPF in the past month will be recruited for qualitative life history interviews. The specific aims of the proposed study are: AIM 1: Provide an in- depth qualitative description of how a rapidly changing heroin/NPF market (type/quality, availability) has impacted injecting heroin/NPF use trajectories (initiation, drug switching, concurrent use) and adverse health related drug risk behavior (overdoses, syringe sharing) in Dayton, Ohio; AIM 2: Examine individual-level perceptions, preferences, and perceived effects regarding synthetic opioids, related strategies for the identification of heroin adulterated with synthetic opioids, and current risk reduction practices among individuals who inject heroin/NPF in Dayton, Ohio; AIM 3: Characterize qualitatively the influence of cultural and social context on strategies, practices, and tactics for safer or riskier behaviors among individuals who inject heroin/NPF in Dayton, Ohio. Proposed Principal Investigator, Tasha Perdue, is a PhD student leading an interdisciplinary research team between faculty from USC and the Wright State University Center for Interventions, Treatment, and Addictions Research. This highly productive collaborative interdisciplinary team is well suited to accomplish the research goals. This research will have an important positive impact by identifying pathways of individuals who are at the highest risk for developing harmful heroin/NPF use trajectories within this distinct social context given the changes in availability of NPF and its analogues. In doing this, the project will lay the foundation for the development and implementation of culturally appropriate targeted prevention and treatment interventions that will reduce risk behaviors of heroin/NPF users that have gone underrepresented in existing research.