BALTIMORE — A sharp decline in U.S. overdose deaths appears to be linked to disruptions in the global supply of illicit fentanyl, according to new research published in the journal Science by a team led by Peter Reuter, a professor of public policy and criminology at the University of Maryland.
After more than a decade of steady increases, overdose deaths in the United States began to fall in mid-2023. Data from the Centers for Disease Control and Prevention show that annual overdose deaths dropped from more than 111,000 in August 2023 to about 69,000 by August 2025. Synthetic opioids, primarily fentanyl, have been involved in roughly three-quarters of all opioid-related deaths in recent years, according to the CDC.
Reuter and his colleagues analyzed multiple data sources to understand what drove the sudden shift. Their findings point to disruptions in the international supply of precursor chemicals used to manufacture fentanyl. These chemicals are largely produced overseas and are essential to the illegal production process.
Law enforcement data from the U.S. Drug Enforcement Administration show that fentanyl seizures declined in 2024 compared with 2023. At the same time, laboratory testing of street drugs found that fentanyl purity dropped, suggesting a less consistent and less potent supply.
The researchers also examined online forums used by people who use drugs. They found that references to a “fentanyl drought” spiked sharply in 2023, far above historical averages. Those conversations often described difficulty finding fentanyl or complaints about weaker products.
“We were trying to understand why fentanyl overdose deaths, after rising rapidly for a decade, suddenly turned downward,” Reuter told The Baltimore Sun following the study’s release. He and his co-authors concluded that changes in supply — not just changes in behavior or policy — played a major role.
Public health efforts also expanded during this period. Naloxone became more widely available, medications for opioid use disorder were easier to access in many states, and more communities invested in harm-reduction strategies. Those efforts clearly saved lives, researchers said, but the timing and scale of the decline suggest that prevention alone cannot explain the full drop.
Similar patterns were seen in Canada, where public health agencies and researchers have also reported supply disruptions and reduced fentanyl potency, followed by declines in overdose deaths.
Health officials caution that the danger is far from over. The CDC notes that overdose deaths remain at historically high levels, and drug markets can change quickly. A restored or stronger fentanyl supply could reverse recent progress.
The University of Maryland study highlights how deeply U.S. overdose trends are tied to global drug markets. Researchers say the findings reinforce the need for a balanced approach that includes prevention, treatment, harm reduction, and monitoring of international supply chains.
