Study Debunks Reported 2025 Drug Overdose Spike

Northwestern University analysis finds statistical modeling error, not true reversal in overdose trends

Apr. 9, 2026 at 12:36pm by Ben Kaplan

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A translucent X-ray photograph showing the ghostly outline of a human skull and ribcage, with faint glowing lines tracing the internal structures, conceptually representing the data-driven analysis that debunked the reported spike in overdose deaths.An X-ray analysis of drug overdose data reveals the statistical modeling behind a reported 2025 spike was an artifact, not a true reversal in declining overdose trends.San Francisco Today

A new Northwestern University study has found that a reported surge in U.S. drug overdose deaths in early 2025, which was based on data from the CDC, was not real. The study found overdose deaths have continued to decline following a peak in August 2023, marking the longest sustained decrease in more than four decades.

Why it matters

Accurate data are essential for public health response. Misinterpreting trends can misdirect policy decisions, undermine public trust and distort resource allocation. Despite this episode, the researchers stress that federal mortality data remain the most reliable near real-time source for tracking overdose death.

The details

The study found the apparent spike was a statistical modeling artifact, not a true reversal in overdose trends. The U.S. relies on provisional mortality estimates from the National Center for Health Statistics, which uses statistical models to account for reporting delays in death investigations. These models performed well for years but struggled when overdose deaths began declining after a prolonged period of rapid growth due to the spread of fentanyl, a synthetic opioid.

  • Overdose deaths peaked in August 2023.
  • The apparent spike in overdose deaths was reported in June 2025.

The players

Lori Ann Post

Lead author of the study and director of the Buehler Center for Health Policy and Economics at Northwestern University Feinberg School of Medicine.

National Center for Health Statistics

The U.S. agency that provides provisional mortality estimates using statistical models to account for reporting delays in death investigations.

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What they’re saying

“Many people think CDC drug overdose data are being cooked, but they're not. We can trust them because they're scientists trying to do the best job they can with difficult circumstances. There was no clear incentive for any administration to inflate these numbers. This was not politics.”

— Lori Ann Post, Director, Buehler Center for Health Policy and Economics, Northwestern University

“What we found was a mismatch between predictive models and a rapidly changing epidemic. CDC scientists did the best job they could with fewer people, more constraints and more people watching them.”

— Lori Ann Post, Director, Buehler Center for Health Policy and Economics, Northwestern University

What’s next

The study authors call for greater transparency in federal data systems, including advance notice of methodological changes and clear documentation of revisions.

The takeaway

This case highlights the importance of understanding the limitations of statistical models and the need for public health data to be transparent, well-documented, and responsive to rapidly changing conditions. It also underscores the ongoing challenges in accurately tracking the opioid epidemic, even as overdose deaths show signs of decline.