OBJECTIVES/GOALS: We aim to develop an understanding of how polysubstance use (PSU) relates to the general psychopathology factor (p-factor), as well as to individual components of the Hierarchical Taxonomy of Psychopathology (HiTOP) model (e.g., fear, distress). This insight can help identify treatment targets related to substance use and psychopathology. METHODS/STUDY POPULATION: Psychopathology and substance use data, collected at a Baltimore treatment center over several years, will be analyzed. The center aids about 6000 underserved clients per year, and the population is primarily African American clients of all genders. Structural equation modeling (using Mplus software) will be used to develop the latent models and identify relationships between psychopathology and PSU (i.e., direct and indirect pathways). The current latent HiTOP model was developed from symptom checklists completed upon entry at the treatment center. The PSU latent factor will be developed from a biopsychosocial assessment where clients list their drug of choice. Due to the varying organizations of the datasets, smaller-scale preliminary models will be developed to ensure an accurate large-scale final model. RESULTS/ANTICIPATED RESULTS: Current models being tested are derived from January to September 2023 data (i.e., completed months' data), with an N of 1,564. From symptom checklist data collected at the treatment center, a preliminary HiTOP model was derived with reasonable fit (χ2 = 4532.35 (df = 321, p<.001), CFI = .77, SRMR = .07, RMSEA = .09 (.089, .094)). Data analysis is being conducted to derive the PSU factor before relating PSU to the HiTOP model. Given previous work at a local treatment center (Pavuluri etal., 2022) and with the National Comorbidity Survey-Replication data, we expect all positive direct relationships, negative indirect relationships between internalizing factors (fear and distress) and PSU when accounting for p-factor, and a positive indirect relationship between antagonism and PSU when accounting for p-factor. DISCUSSION/SIGNIFICANCE: Given our previous work to develop such models, we want to establish proof of concept in alarger treatment center population. This confirmation will help provide a path towards conducting therapeutic trials to target psychopathology when treating substance use given the shared relations, some of which are less understood (e.g., fear and PSU).