The purpose of this notice of funding opportunity (NOFO) is to solicit applications proposing mechanistic transdisciplinary research in animal models that integrates approaches across social/cognitive neuroscience with perspectives from fields with complementary approaches to the study of social behavior, with the goal of developing a testable conceptual or computational model that provides mechanistic insights into social behavior and its relationships with the onset, trajectory and impact of Substance Use Disorders (SUD) and comorbidities. This NOFO is intended to support basic or translational research in non-human animal models, including secondary analysis of data from research in animal models. Applications including studies involving human subjects should submit under one of the companion NOFOs.