Qasmieh, NoorSocial anxiety disorder (SAD) in adolescence is heterogeneous in presentation and often associated with substance use behaviors. Yet, little is known about the link between these constructs. One framework of SAD identifies a subtype of behaviorally dysregulated, socially anxious individuals. Because the suite of goal-directed, cognitive processes known as executive functioning serves as a precursor to behavior regulation, we sought to explore whether heterogeneity in social anxiety presentation meaningfully varied with executive functioning in early adolescence and if this model of heterogeneity could predict substance use and other clinical outcomes. Using a person-centered approach to modeling, latent class analysis, a sample of over 10,000 children from the longitudinal Adolescent Brain and Cognitive Development (ABCD) study was used to model variation in social anxiety symptoms and performance on assessments of working memory, cognitive flexibility, and inhibition. We also examined construct validity of the model by exploring associations with concurrent measures of behavioral inhibition, behavioral activation, and impulsivity. Finally, we tested the extent to which the identified model predicted later measures of substance use behavior, peer problems, and psychopathology. Support for a four-class solution of SAD symptoms and executive functioning performance was identified. Classes of individuals meaningfully differed on measures of behavioral inhibition and facets of impulsivity. Class membership was also predictive of later internalizing psychopathology. However, class membership did not predict later substance use, externalizing psychopathology, or peer problems. Future work should explore the generalizability of this model to older adolescents and whether alternative measurements of SAD and EF strengthen our prediction of later outcomes.enDissertationClinical psychology