Cumulative impact of substance use disorders, mental illness, and marginalization on health system utilization patterns

The increasing complexity of healthcare demands is shaped not only by medical conditions but also by the cumulative effects of behavioral health challenges and social marginalization. Individuals facing substance use disorders (SUD), mental illness, and socioeconomic marginalization often experience disproportionately high rates of health system utilization. These intersecting vulnerabilities result in a syndemic—a convergence of multiple health and social issues that exacerbate individual outcomes and stress healthcare systems. From emergency department visits to repeated hospital admissions, this population tends to access acute care services more frequently than the general population, often due to unmet needs in primary care, community-based mental health support, and housing stability. Marginalization—through homelessness, racial discrimination, poverty, or criminal justice involvement—further restricts access to preventative and consistent healthcare, reinforcing a cycle of crisis-based utilization. When combined with SUD and mental illness, these factors produce a synergistic burden, leading to fragmented care, higher costs, and poorer outcomes. Despite these systemic challenges, many healthcare models remain ill-equipped to address the layered and overlapping needs of these populations. This review examines the cumulative impact of SUD, mental illness, and marginalization on health system utilization patterns, integrating theoretical frameworks such as syndemic theory and intersectionality. It explores utilization trends, identifies structural barriers, and highlights integrated care solutions and policy responses aimed at improving health equity and reducing systemic strain. Ultimately, the article argues for a paradigm shift toward trauma-informed, inclusive, and coordinated care systems that address the full spectrum of biopsychosocial vulnerabilities in marginalized populations.