Co-treating Opioid and Alcohol Use Disorders in the United States, 1960-2026: A Historical Policy Review in the Glucagon-Like Peptide-1 (GLP-1) Era

This narrative review reconstructs the U.S. history of treating co-occurring opioid use disorder (OUD) and alcohol use disorder (AUD) from the rise of methadone maintenance in the 1960s through contemporary interest in immunometabolic mechanisms and repurposed therapies. Drawing on peer-reviewed literature and selected grey sources, we trace four eras including early single-substance paradigms and maintenance; federally regulated opioid treatment programs and the broader medicalization of addiction care; recognition of co-occurring disorders, parity and Affordable Care Act reforms, and uneven diffusion of medications for OUD and AUD; and a renewed metabolic framing, including preclinical, clinical, and real-world evaluation of glucose-dependent insulinotropic polypeptide (GIP)/glucagon-like peptide-1 (GLP-1) receptor agonists. Across eras, regulation, reimbursement, and professional authority shaped access as much as evidence, producing persistent geographic and socioeconomic inequities. Emerging GLP-1-based therapies may offer a distinctive cross-disorder adjunct, but their value for OUD/AUD remains unproven. Population benefit will require rigorous trials and delivery reforms that expand equitable access to integrated care.