Abstract
The current opioid epidemic is the worst drug epidemic the U.S. has ever faced. We examine the role of social connections in its spatial spread. Having many friendship links to counties with high opioid exposure positively correlates with overdose death rates. To address identification concerns, we exploit two quasi-natural experiments that led users to substitute illicit opioids for prescription drugs. Having more friends exposed to counties affected by these shocks leads to more overdose deaths. We also provide suggestive evidence that spillovers affect different stages of addiction, are influenced by both supply- and demand-side conditions, and are attenuated in counties with more cohesive local friendship networks. Our results show how social connections contribute to the spread of the opioid epidemic.