Summary/Abstract Cerebral Palsy (CP) is the most common pediatric-onset physical disability, with an estimated prevalence ranging from 2.6-3.1 cases per 1,000 live births in the United States. There is a lack of clinical follow-up for patients with CP after they transition from pediatric to adult primary care, and insufficient cohort data to track clinical outcomes longitudinally. Pain is the most commonly reported somatic symptom in CP throughout the lifespan, and yet chronic pain is perhaps the least understood, emphasized, and studied physical comorbidity of CP. Pain in CP may arise from nociceptive mechanisms associated with chronic muscle spasticity, joint misalignment, and invasive and repetitive surgical procedures. Alternatively, neuropathic pain could be a consequence of periventricular leukomalacia, which causes dysfunction of non-nociceptive sensory tract neurons in the majority of patients with CP. To date, there have been virtually no investigations to understand the pain phenotype distribution and treatment disparities among adults living with CP, and how differing pain management strategies contribute to physical and psychological morbidity and multimorbidity. Understanding the phenotypes of chronic pain among adults with CP is crucial for prescribing the most appropriate and effective pain management interventions. This innovative study proposes to examine the risk of pain and multimorbidity among adults with CP as compared to adults without CP, and to further understand the role of race/ethnicity and insurance type (Medicare vs. private) on pain management. Although understanding the mechanisms of pain among adults with CP is crucial for prescribing the most appropriate and effective pain management interventions, many adults with CP currently receive opioid prescriptions. Therefore, it is vital to also examine the short and long-term effects of these analgesics and alternative treatments/therapies on long- term health outcomes in this population. It is also critical to examine the extent to which mismanaged pain mediates the trajectories leading to chronic morbidity and multimorbidity in this population. The study we propose herein fills this critical gap in knowledge by leveraging several unique datasets representing a population-representative sample of federally- and privately insured beneficiaries of U.S. adults with CP. Our objectives, foundational to developing such targeted interventions, are to compare the prevalence and incidence of chronic nociplastic, neuropathic, and nociceptive pain among privately and federally insured adults with CP throughout the U.S (Aim 1); and quantify the mediating effect of chronic pain and opioid prescribing patterns on physical and mental health morbidity and multimorbidity among persons with CP (Aim 2). Lastly Aim 3 will determine the disparities in and effectiveness of pain management/treatment strategies by race/ethnicity and insurance type, taking into account the social determinants o...