Drivers of the fatal drug epidemic.

This study examines the contributions of the medium-run evolution of local economies and of changes in the "drug environment' in explaining county-level changes in drug and related mortality rates from 1999 to 2015. A primary finding is that drug mortality rates did increase more in counties experiencing relative economic decline than in those with more robust growth, but that the relationship is weak and mostly accounted for by confounding factors. In the preferred estimates, less than one-tenth of the rise in drug and opioid-involved fatality rates is explained and the contribution is even smaller, quite possibly zero, when allowing for plausible selection on unobservables. Conversely, the risk of drug deaths varies systematically over time across population subgroups in ways that are consistent with an important role for the public health environment related to the availability and cost of drugs. In particular, the relative risk and share of drug mortality increased rapidly for males and younger adults, compared to their counterparts, when the primary driver of the fatal drug epidemic transitioned from prescription to illicit opioids. These results suggest that efforts to improve local economies, while desirable for other reasons, are not likely to yield significant reductions in overdose mortality, but with greater potential for interventions directly addressing the drug environment.