Characterizing Declines in US Overdose Deaths Compared to Exponential Predictions
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Importance
After decades of growth described nearly perfectly with an exponential curve, US overdose mortality has begun to decrease.
Objective
To determine whether decreases in overdose mortality between 2023 and 2024 deviate from a previously defined exponential growth curve, and assess how they differ by substance involvement, geography, race/ethnicity, demographic, and other key dimensions.
Design, Setting, and Participants
Observational study examining overdose deaths in the US between January 1980-December 2024. Mortality trends were compared to an exponential growth curve, fit on data from 1980 to 2016.
Exposures
Year and month of occurrence of overdose death; substance involvement; census region and division; state; county; race/ethnicity, age, and sex.
Main Outcome and Measures
Annual or monthly (annualized) overdose deaths per 100,000 population.
Results
After precipitously surpassing exponential growth predictions in 2020-2023, overdose deaths fell sharply from approximately 32 per 100,000 in 2021-2023 to 23.7 in 2024, below the lower bound of the exponential curve prediction (24.98) for the first time since 2001. Monthly data show consistent decreases between June 2023 and December 2024. Decreases reflected declining illicit fentanyl-involved deaths (with and without stimulants); however, deaths involving stimulants without fentanyl, and those involving xylazine, continued to increase in 2024. Death rates in the Northeast, South and Midwest fell to 19.5, 19.4 and 17.3 per 100,000, respectively, in December 2024, but remained elevated in the West at 27.2 per 100,000. Non-Hispanic Black and African Americans had the largest decrease in death rates in 2023-2024 falling 29.3%, but remained elevated at 36.0 per 100,000, compared to the national average of 23.7 per 100,000. Non-Hispanic American Indian and Alaska Native individuals had the highest overdose mortality rate in 2024, at 50.8 per 100,000.
Conclusions and Relevance
Recent decreases in overdose deaths are encouraging, unprecedented, and represent the first significant, large-magnitude deviation below exponential growth. However, policymakers, clinicians, and public health officials should be prepared for the possibility that a resurgence could occur, especially if novel synthetic drugs change the risk environment of illicit drug use. Stimulants and xylazine continue to represent increasingly important public health challenges. Racial gaps remained large but shrunk by a modest margin.
Key Points
Question
To what extent are recent decreases in US overdose mortality deviating from prior exponential growth, and how have substance-specific, racial/ethnic, and geographic trends shifted?
Findings
Decreases in overdose deaths between June 2023 and December 2024 represent the first significant large magnitude drop below the exponential growth curve, driven by falling illicit fentanyl mortality. However, deaths involving stimulants and xylazine continue to rise. The Western US shifted from the least-affected region to the most affected by overdose mortality. Racial gaps remain large but shrunk by a modest margin.
Meaning
The course of the US overdose crisis is no longer consistent with an exponential growth curve, but novel substances and adulterants represent a potential driver of increased deaths in the future. Shifts occurring in 2024 were disproportionate by geography and race/ethnicity.
