Project Summary Social connection with close others is a fundamental human need. Feeling connected to others reliably and robustly predicts health and wellbeing whereas feeling disconnected or isolated from others negatively impacts health. Less well understood, however, are the processes by which subjective feelings of social connection are maintained over time. Endogenous opioids may contribute to social connection with close friends, romantic partners, and family. Specifically, naltrexone, a common medication prescribed to assist in the recovery from addiction that blocks the action of naturally occurring opioids, unfortunately leads to a reduction in feelings of social connection toward close others in an otherwise healthy sample. These findings raise the possibility that the medication used to treat addiction may introduce an unintended barrier to one of the most effective contributors to long-term maintenance: close social relationships. Based on these findings, there has been a growing interest in whether opioid pathways contribute to feelings of social connection with close others in a causal manner and how these effects might occur. The primary objective of the parent project is to clarify the causal role of opioids in (1) daily, naturalistic feelings of social connection outside of the laboratory, (2) the neural signatures of feelings of social connection, and (3) feelings of social connection in response to personalized experiences with friends and family using standardized laboratory tasks. For the current supplement to promote diversity in health science, a post-baccalaureate candidate, Ms. Isabela Cruz-Vespa, will lead a new cross-sectional survey study to extend Aim 1 and assess the association between feelings of social connection and reported drug use. Thus, over the course of a one-year rotation in the PI’s laboratory, the candidate will implement a research study from the beginning to end and will also have the opportunity to present at internal and national conferences. To further enhance the candidate’s research experience in the lab, the candidate will receive training on the methods used in the parent project, including neuroimaging, ecological momentary assessment, and drug administration. Finally, the candidate will receive extensive one-on-one mentoring to prepare her for application to graduate school, and independent funding, and will complete professional and career development activities that increase the strength of her CV.