A Novel Compartmental Model for the Mathematical Epidemiology of Addiction: Backward Bifurcation, Bistability, Persistence, and Treatment-Capacity Policy Implications
This paper develops a novel four-compartment epidemiological model for addiction dynamics that demonstrates how treatment-capacity saturation, rather than incidence saturation, uniquely drives backward bifurcation and bistability, creating a critical policy gap where the basic reproduction number fails to capture the risk of long-term persistence even below traditional thresholds.