U.S. Overdose Deaths Plunge 24% in 2024 as Fourth Wave Recedes, But Stimulant Crisis Looms

America's overdose crisis has reached a historic inflection point. New research from the University of California San Diego published in the journal Addiction documents a dramatic 24.4% decline in overdose death rates between 2023 and 2024—the first recorded decrease across all four waves of the nation's prolonged substance use epidemic.

The findings, based on comprehensive analysis of CDC mortality data spanning 1999 to 2024, reveal that deaths involving illicit fentanyl fell sharply last year, including fatalities from fentanyl combined with stimulants such as methamphetamine and cocaine. Yet the same research exposes emerging threats that could reshape the landscape of addiction-related mortality: stimulant-only overdose deaths continue climbing, xylazine contamination is spreading, and profound racial disparities persist despite overall improvements.

The Four Waves and Their Unprecedented Retreat

Researchers have long characterized the U.S. overdose epidemic as unfolding in four distinct phases. The first wave involved prescription opioids, followed by heroin, then illicit fentanyl, and most recently the lethal combination of fentanyl with stimulants—a pattern termed the "fourth wave" that has proven especially deadly due to polysubstance use.

The new study demonstrates that this fourth wave declined for the first time in 2024. The national overdose death rate fell to 23.7 deaths per 100,000 people, down from higher levels that had persisted for years. The primary driver was a substantial reduction in fentanyl-related fatalities.

Deaths involving fentanyl without stimulants dropped from 31,193 in 2023 to 19,673 in 2024—a 37% decrease. Deaths involving fentanyl combined with stimulants fell from 41,583 to 28,062, representing a 32% reduction. These declines account for the majority of the overall mortality improvement.

"We are seeing a historic shift in the overdose crisis," said Dr. Joseph Friedman, the study's first author and resident physician in psychiatry at UC San Diego School of Medicine. "But this is not the end. The substances involved are changing, some parts of the crisis are still growing, presenting new challenges."

The Rising Stimulant Threat

While fentanyl deaths receded, fatalities involving stimulants without opioids moved in the opposite direction. Deaths from methamphetamine and cocaine alone increased from 18,142 in 2023 to 18,907 in 2024—a 4% rise that masks a more significant shift in the composition of the crisis.

These stimulant-only deaths accounted for 17.3% of all overdose fatalities in 2023 but grew to 23.8% in 2024. If current trends continue, researchers warn, stimulants could soon surpass opioids as the defining addiction-related public health challenge in the United States.

"Overdose deaths are only one part of the picture," noted senior author Dr. Steffanie Strathdee, professor of medicine at UC San Diego. "Stimulants are also associated with long-term cardiovascular, neurological and psychiatric harms that can devastate individuals and communities."

Unlike opioids, which have well-established pharmacological treatments including naloxone for overdose reversal and medication-assisted treatment for long-term management, stimulant use disorders lack FDA-approved medications. This treatment gap leaves patients dependent on behavioral interventions and psychosocial support alone.

Xylazine and the Evolving Drug Supply

The study also identified xylazine, a veterinary sedative increasingly detected in the illicit drug supply, as a growing concern. Xylazine-related overdose deaths rose during the study period, with the substance now implicated in a growing share of fentanyl-involved fatalities.

Xylazine presents unique challenges for overdose response. The sedative does not respond to naloxone, the standard medication for reversing opioid overdoses, and its presence in fentanyl mixtures complicates emergency medical interventions. Users who consume xylazine-adulterated drugs may experience severe withdrawal symptoms and distinctive wounds requiring specialized medical care.

Persistent Racial Disparities

Perhaps the most troubling finding involves the uneven distribution of progress. While overdose deaths declined across all racial and ethnic groups, the magnitude of improvement varied dramatically—and baseline disparities remain stark.

Non-Hispanic Black individuals experienced the largest relative decline, with overdose death rates falling 29.3% between 2023 and 2024. However, the overdose death rate for Black Americans remained more than 1.5 times higher than the national average in 2024.

The non-Hispanic American Indian and Alaska Native population faced the highest overdose death rate of any group studied: 50.8 deaths per 100,000 people, more than double the national average. This disparity persisted even as overall mortality declined.

Cocaine-related deaths disproportionately affected Black Americans, while methamphetamine-related deaths disproportionately impacted American Indian and Alaska Native communities. Xylazine-related fatalities also showed elevated rates among Black Americans.

"National trends can improve while vulnerable communities continue to suffer disproportionately," Friedman said. "The next phase of the response needs to focus not only on lowering overall deaths, but on making sure those gains reach the populations that have been hit hardest."

Explaining the Decline

The causes of the 2024 reduction in overdose deaths likely reflect multiple intersecting factors. Researchers suggest several possible contributors:

Reduced susceptible population: After years of devastating mortality, there may simply be fewer high-risk individuals in the population.

Increased awareness: Greater public recognition of fentanyl's dangers may have led to behavioral changes among people who use drugs.

Expanded naloxone access: Wider distribution of overdose reversal medication has likely prevented numerous fatalities, though this primarily affects opioid-involved overdoses.

Supply disruptions: Possible interruptions in the illicit fentanyl supply chain may have temporarily reduced availability.

Treatment expansion: Increased access to opioid addiction treatment, including medication-assisted treatment with buprenorphine and methadone, may have reduced mortality among people with opioid use disorders.

The researchers caution that provisional 2024 mortality data could still change slightly as final records become available, though the overall trend appears robust.

Global Context and Continuing Challenges

Even with the recent decline, overdose deaths in the United States remain extraordinarily high compared to other developed nations. Approximately 80,000 people died from drug overdoses in the U.S. in 2024—far more than would be expected if the country had overdose death rates comparable to Western Europe.

The United States continues to be a global outlier in addiction-related mortality, a distinction that reflects complex factors including drug policy choices, healthcare system characteristics, and the unique evolution of the American illicit drug market.

Looking Forward

The 2024 data suggest that the overdose crisis is entering a new phase—one characterized by declining overall mortality but shifting patterns of substance involvement and persistent inequities in who benefits from progress.

For people struggling with opioid addiction, the findings offer reason for cautious optimism: expanded treatment access and harm reduction efforts appear to be saving lives. But the rising stimulant toll serves as a reminder that addiction is a moving target, with new challenges emerging as old ones recede.

The research underscores the need for continued investment in addiction treatment infrastructure, harm reduction programs, and targeted public health interventions designed to reach the communities still experiencing disproportionate harm. The fourth wave may be receding, but the underlying currents of substance use and addiction continue to shape American public health.

The study was funded by the National Institute on Drug Abuse and published in the peer-reviewed journal Addiction.