This week’s NDEWS Weekly Briefing focuses on Emergency Medical Service (EMS) encounters involving suspected nonfatal overdoses involving fentanyl and separately for methamphetamine across 11 of our Sentinel Sites from July 2024 through July 2026. We also compared the rates per 10,000 for each drug and for each of the Sentinel Site counties for the time frames and compared them to the rates for the US. They show interesting patterns of increases and decreases by drug and highlight the utility of the Sentinel Sites in the NDEWS ecosystem. 

Additionally, our latest NDEWS Web Monitoring Report analyzed Reddit discussions related to polysubstance use, providing insight into how individuals discuss the co-use of opioids, stimulants, alcohol, and other substances in online communities.

As substance use patterns continue to evolve, recent research underscores the importance of understanding polysubstance use, including the co-use of opioids, stimulants, alcohol, and other substances. 

Finally,  you won’t want to miss our international expert, Chris McCurdy, speaking about kratom and 7-OH on September 23. See the link in the announcement below. 

As always, we welcome your input.

Click here for a PDF version of the report.

Click here to learn more about the NDEWS Special Reports.

Why are we reporting on this? Polysubstance use is a recurring topic across Reddit discussions, with commenters describing combinations involving opioids, stimulants, alcohol, benzodiazepines, cannabis, psychedelics, dissociatives, and other substances. Discussions highlight patterns of rotating or combining substances to alter effects, manage unwanted effects, maintain intoxication, or address tolerance, alongside concerns about dependence, interactions, and difficulty controlling use.

What is Polysubstance Use? Polysubstance use involves the simultaneous, concurrent or sequential use of more than one psychoactive substance. Reddit discussions include combinations spanning multiple drug classes, including opioids and stimulants, alcohol and benzodiazepines, cannabis and psychedelics, MDMA and other stimulants, and psychedelics with dissociatives or other substances.

Public Health Impacts: Reddit discussants describe recurring concerns associated with polysubstance use, including anxiety, nausea, confusion, memory difficulties, sleep disruption, and other cognitive effects. Multiple discussions also describe patterns of tolerance, dependence, relapse, and difficulty maintaining controlled use when substances are combined or alternated. Effects vary depending on which substances are involved.

How is it Being Discussed? Reddit commenters engage in detailed discussions regarding pharmacological synergies, receptor mechanisms, and metabolic interactions across multiple drug classes, often seeking to enhance, modify, or balance psychoactive effects. A substantial focus centers on festival and recreational environments where individuals combine MDMA with other substances, prompting extensive warnings to avoid use of alcohol, cocaine, or other stimulants due to heightened risks of dehydration, elevated body temperature, and compounded cardiovascular strain. Commenters also frequently discuss complex interactions between recreational substances and prescribed psychiatric medications, specifically highlighting the adverse risks of combining monoamine oxidase inhibitors, selective serotonin reuptake inhibitors, or bupropion with entactogens. Beyond party settings, discussions detail broader polysubstance patterns where individuals cycle between or concurrently administer stimulants, opioids, benzodiazepines, and GHB modulators to mitigate anxiety, counter side effects like nausea, or substitute one agent for another. Additionally, community members frequently discuss co-administering cannabis or dissociatives such as ketamine and dextromethorphan with classic psychedelics and novel tryptamines, noting that these mixtures can amplify subjective intensity, visual distortions, and acute paranoia when multiple compounds impact overlapping physiological systems.

Search Terms: co use, co-use, mixed, mixing, mixture, polysubstance, poly substance, poly use, combination, combined, combine, together, stack, stacking, at the same time

Click here for more information on NDEWS Online Monitoring.

A recent publication in Substance Use & Addiction Journal by Cadet et al. discusses policy changes to address opioid-stimulant polysubstance use, which has increased substance use-related morbidity and mortality. The authors outline three policy areas in need of reform: opioid agonist treatment policy, payment for evidence-based treatment, and drug paraphernalia laws. The commentary emphasizes that addressing the current polysubstance use overdose crisis requires a shift toward patient-centered policies that expand access to comprehensive evidence-based treatments and services for individuals engaged in opioid-stimulant polysubstance use.

Ready the full study here.

A recent in press publication in Scientific Reports by Quddos et al. investigated delay discounting and proportion of remission among individuals with polysubstance use disorder. The study found that delay discounting, maximum time in recovery, and maximum quit time were significantly associated with proportion of remission. The authors report that interventions that focus on risk reduction and/or modulate delay discounting may lead to improved clinical outcomes, including quit time and proportion of remission, in individuals with a history of polysubstance use.

Ready the full study here.

A recent in press publication in BMC Public Health by Albert et al. examined the prevalence, patterns, and self-reported harms associated with polysubstance use in Canada using data from the 2023 Canadian Substance Use Survey. Past-year polysubstance use was reported by 27.2% of respondents and was predominantly alcohol-involved, with common patterns including alcohol plus cannabis and alcohol plus stimulants. Compared with single-substance use, drug-plus-alcohol polysubstance use was associated with reporting any harm. The authors conclude that integrating alcohol into polysubstance prevention, screening, and surveillance frameworks may strengthen public health responses to substance-related harms.

Ready the full study here.

Christopher R. McCurdy, Ph.D., FAAPS, is a broadly trained medicinal chemist, behavioral pharmacologist and pharmacist whose research focuses on the design, synthesis and development of drugs to treat pain and drug abuse. During the upcoming NDEWS Webinar on September 24, Dr. McCurdy will discuss 7-hydroxymitragynine (7-OH) and other recently scheduled synthetic substances.

📅 Date: September 24, 2026

🕑 Time: 1 pm - 2 pm ET

📍 Location: Virtual via Zoom

Register for the webinar here.

Are you committed to advancing the science of substance use and public health? The University of Florida’s NIDA-funded T32 Training Program offers predoctoral and postdoctoral scholars an exceptional opportunity to launch impactful research careers focused on NDEWS!

What We Offer:
- Interdisciplinary training at the intersection of addiction science, epidemiology, and surveillance
- Mentorship from leading UF faculty in epidemiology, public health, psychology, medicine, and more
- Hands-on research with landmark and important NIH-funded projects and access to rich data
- Career development support, including grant writing, publishing, and professional networking
- A collaborative, inclusive research community committed to reducing the burden of substance use

Eligibility:
- US citizens or permanent residents
- Interested in a PhD in Epidemiology, or early-stage postdoctoral fellows
- Demonstrated interest in substance use, addiction, or public health research

Location: Gainesville, Florida — a dynamic hub for scientific innovation with high quality of life and low cost of living.

The NDEWS Weekly Briefing curates emerging data and findings from across the Early Warning Network, which includes three core components: our Scientific Advisory Group (SAG), comprised of national experts and federal partners; our Sentinel Site Directors (SSDs), who lead local surveillance in key geographic regions; and our Community-Based Health Experts, who provide on-the-ground insights from populations most impacted by drug trends. Together, these contributors generate timely, multidisciplinary and impactful information, ranging from peer-reviewed research findings to local surveillance data. These contributions inform public health and research communities.

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If you miss or want to learn more about NDEWS Original Content, you can find our archived content on the NDEWS website:

     • NDEWS Special Reports using substance-related EMS data
     • NDEWS Rapid Street Reporting (RSR) survey data reports
     • NDEWS Web Monitoring Team Reddit Alerts
     • NDEWS Sentinel Site Reports
     • Previous issues of the NDEWS Weekly Briefings

The Weekly Briefing is a newsletter published each week by the National Drug Early Warning System (NDEWS) Coordinating Center, which is funded by the National Institute on Drug Abuse (U01DA051126) to the University of Florida (MPI: Cottler (contact), Co-Is: Goldberger, Nixon, Striley), NYU Langone Health (MPI: Palamar), and Florida Atlantic University (Co-I: Barenholtz). 

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