A new study, based on data from the U.S. and Canadian governments and discussions on Reddit, suggests that the recent decline in U.S. overdose deaths was driven in large part by a sudden shift in the drug supply in 2023.

The findings:

The paper suggests that the drop in deaths stems from a decrease in fentanyl potency, driven by Chinese government crackdowns on groups that traffic precursor chemicals.
The drop in potency lead to a surge in online mentions of terms like “drought” and a decline in overall fentanyl seizures by law enforcement.
But: The researchers have no explanation for why the effect of precursor control has not worn off (i.e., traffickers finding new source ingredients, turning to other potential chemical markets like India). The supply shock also fails to account for geographic variation.

The bigger picture: Experts have struggled to explain the decrease in overdose deaths. Other theories include a return to the pre-COVID status quo, the success of treatment and harm reduction policies, and the reality that many of the most vulnerable people using substances already died.

But: The researchers of this study suggest that it is unlikely that any of these factors could fully explain the sudden decrease, except for a drug supply shock. But they allowed that some of the decrease could be the result of demand-side factors and noted that finding data to accurately assign credit to various factors would be difficult or impossible.
They also note that the findings do not mean that the U.S. government should be interested in more supply control and that they do not “make locking up lots of drug dealers a more effective way of dealing with the problem. The sensible policy by the U.S. government is treatment and prevention.”
Researchers warn that supply shocks are often temporary and that the illicit opioid supply could become more potent again in the future.