Preliminary data from the U.S. Centers for Disease Control and Prevention suggests that drug-overdose deaths declined more than 16% between June 2023 and June 2024, the biggest drop in a decade marked by staggering increases. University of Illinois Urbana-Champaign health and kinesiology professor Rachel Hoopsick, an epidemiologist who studies mental health challenges and substance use in populations at risk, spoke with News Bureau life sciences editor Diana Yates about recent drug-use trends.

Media reports about new data suggest the fentanyl epidemic, which drove a lot of the recent increases in drug-overdose deaths, has peaked and is now in decline. Is this true, and if so, do we know why?

It’s true that overall, drug overdose deaths in the U.S. have recently declined. At face value, this looks encouraging, but this doesn’t tell the whole story.

Can leaders point to any public policy actions that are contributing to the decline in fentanyl use or drug-overdose deaths?

While pundits point to increased law enforcement efforts or strides in prevention and treatment efforts, the reality is that there are multiple explanations for this trend and a number of nuanced factors at play. I don’t think we’ve had truly robust public policy actions in the U.S. that we can point to that would have resulted in such a sudden and profound downturn in mortality.

What factors might be at play?

If you ask any epidemiologist about the examination of complex health-related phenomena, you’ll often get the answer: “It depends.” There are several major factors to consider:

First, whenever we observe sudden and steep changes in overdose mortality — in either direction — we should first look at the toxicity of the street drug supply before assuming that there have been drastic population-level changes in behavior. Some data suggests that there have been recent shifts in the types and concentrations of the substances, called adulterants, that street drugs are “cut” with. Although fentanyl-only deaths have declined, we’re seeing increases in deaths that co-involve fentanyl and stimulants, like methamphetamine. There have also been increases in nonopioid sedative adulterants, like xylazine. This underscores the importance of public health lab research that monitors the pharmacoepidemiology of the street drug supply, which can serve as an early warning system.

Second, although there have been population-level declines in overdose mortality, these numbers have largely been driven by a steep reduction in overdose deaths among white people, while drug-related deaths in communities of color continue to increase, particularly among Black and Native American adults. This widening disparity isn’t reflected in overall trends.

Third, it’s a depressing concept, but another factor is what we call “depletion of susceptibles.” In this context, it’s possible that we’re seeing such a decline in overdose deaths because those who were most vulnerable to overdose have already died, meaning that over time, we observe fewer and fewer overdose deaths.

Tens of thousands of people are still dying each year in the U.S. from preventable drug overdoses. Is the decline just a normal fluctuation in complex data, or might it be a sign of a long-term trend?

The data suggest that this is more than normal fluctuation, but it remains to be seen whether this trend will continue. Despite the overall downward trend at the population level, the reality for individuals who use drugs is that the street drug supply remains highly toxic, overdose risk remains incredibly high and access to harm reduction and treatment services remains low. I think it’s too early to celebrate the decline in overdose deaths. We shouldn’t accept 100,000 needless deaths a year.

What policy, harm reduction or treatment approaches might help the trend continue?

Looking at past data from the U.S. and other countries, we should be wary of the direction of where our drug policies will go from here. The next administration is focused on stricter border control measures and criticizing harm-reduction programs, which have been instrumental in addressing the overdose crisis. Rolling back these programs and doubling down on punitive strategies that have proven ineffective — see The Iron Law of Prohibition: “the harder the enforcement, the harder the drugs”— is unlikely to sustain progress or save lives, but rather runs the risk of exacerbating the problem.