Who Is Co-Using Nicotine, Alcohol, and Cannabis — and How Is That Changing?
A nationally representative US study using five years of PATH Study data tracks how co-use of cigarettes, e-cigarettes, and other tobacco products with alcohol and cannabis has shifted across age groups from 2016 to 2021, revealing that e-cigarette co-use is displacing cigarette co-use among younger populations.
Why This Matters
Polysubstance use is the norm rather than the exception in substance-related clinical encounters, yet most research and most treatment frameworks address single substances in isolation. The US tobacco and cannabis markets have undergone rapid transformation over the past decade, with e-cigarette adoption surging among younger users and cannabis legalization spreading state by state. Understanding how these market shifts reshape real-world co-use patterns across age groups is essential for designing targeted prevention strategies, anticipating emergent health risks, and tailoring clinical conversations about substance use to specific patient populations.
Clinical Summary
The co-use of nicotine or tobacco products with alcohol and cannabis represents a major public health challenge, as combined exposure may produce interactive harms that exceed the sum of individual substance risks. This study, published in Preventive Medicine, draws on Waves 4 through 6 of the nationally representative Population Assessment of Tobacco and Health (PATH) Study, spanning December 2016 to November 2021. The investigators constructed six binary co-use outcomes by crossing three tobacco product categories (cigarettes, e-cigarettes, and other tobacco products) with two substances (alcohol and cannabis), then modeled trends across five age strata using survey-weighted interaction analyses controlling for demographic characteristics. The design leverages the PATH cohort’s replenishment sampling to maintain national representativeness over time.
The central findings reveal a product substitution dynamic in younger populations. Cigarette and alcohol co-use, while still the most prevalent pattern among adults overall, declined significantly among 18 to 24 and 25 to 34 year-olds. E-cigarette and alcohol co-use increased among young adults and emerged as the dominant co-use pattern among youth aged 15 to 17, though youth prevalence followed an inverted-U trajectory, rising and then falling. E-cigarette and cannabis co-use spiked at Wave 5 across all younger groups but persisted through Wave 6 only among 25 to 34 year-olds. The authors note that full effect sizes and confidence intervals were not available in the extracted data, limiting precision assessment. They emphasize that these descriptive trends cannot establish causality and that age-stratified, product-specific intervention strategies are needed before translating these patterns into clinical recommendations.
Dr. Caplan’s Take
This study does something genuinely useful: it maps the terrain of polysubstance use in a way that reflects what clinicians are actually seeing. The shift from cigarette co-use to e-cigarette co-use among younger patients is not surprising to anyone practicing in this space, but having population-level confirmation matters. When a 22-year-old tells me they vape, drink socially, and use cannabis occasionally, they are describing the statistically dominant co-use pattern for their age group. The gap, as always, is that we know far less about the combined health consequences of these newer patterns than we do about the cigarette-and-alcohol combination that has been studied for decades.
In practice, I screen for co-use explicitly rather than asking about substances one at a time. These data reinforce that approach. When patients present with symptoms that could involve nicotine, alcohol, or cannabis, I ask about all three in the same conversation, and I pay particular attention to e-cigarette use in younger patients, where it has become the primary gateway to polysubstance patterns. Interventions that only target one substance at a time are likely missing the clinical reality for most of these individuals.
Clinical Perspective
This study sits at an important juncture in the substance use research arc. Prior surveillance work has documented the decline in youth cigarette smoking and the rise of e-cigarette use independently, but relatively few studies have characterized how these shifts interact with alcohol and cannabis use patterns across age groups in a single analytic framework. The finding that age group moderates nearly every trend underscores a critical point for clinicians: population-level averages obscure dramatically different realities for a 20-year-old versus a 50-year-old patient. These data support the clinical practice of age-stratified screening but do not yet provide evidence that any specific co-use pattern causes worse outcomes than individual substance use alone.
From a safety standpoint, the pharmacological interactions between nicotine, alcohol, and cannabis remain incompletely characterized, particularly for e-cigarette delivery of nicotine, which produces different pharmacokinetic profiles than combustible cigarettes. Clinicians should be aware that concurrent cannabis and alcohol use is independently associated with impaired driving risk and cognitive effects, and the addition of high-concentration nicotine via e-cigarettes may alter reward processing and dependence trajectories in ways not yet captured by clinical guidelines. The single most actionable step is to adopt a co-use screening protocol for all patients under 35 that asks specifically about e-cigarettes, alcohol, and cannabis use within the same 30-day window, rather than relying on separate substance-specific questions.
Study at a Glance
| Study Type | Longitudinal cohort study with repeated cross-sectional analysis (secondary analysis of PATH Study Public Use Files) |
| Population | US non-institutionalized individuals aged 15 and older enrolled in PATH Waves 4 through 6 |
| Intervention | Not applicable (observational surveillance study) |
| Comparator | Age-stratified and wave-stratified prevalence comparisons across five age groups |
| Primary Outcomes | Six binary co-use variables: cigarette, e-cigarette, or other tobacco product use combined with alcohol or cannabis use in the past 30 days |
| Sample Size | PATH Study Waves 4 through 6 nationally representative sample (exact cell-level sizes not available in extracted text) |
| Journal | Preventive Medicine |
| Year | 2024 |
| DOI or PMID | Not available in extracted text |
| Funding Source | PATH Study funded by the National Institute on Drug Abuse (NIDA) and the FDA Center for Tobacco Products |
What Kind of Evidence Is This
This is an original quantitative cohort study using secondary analysis of a nationally representative longitudinal survey. It occupies a position in the evidence hierarchy above cross-sectional surveys but below experimental designs. The most important inference constraint is that the study describes trends and associations in co-use prevalence but cannot establish causation, meaning it cannot determine why co-use patterns changed or whether any observed shifts led to specific health outcomes.
How This Fits With the Broader Literature
These findings are broadly consistent with national surveillance data from the National Survey on Drug Use and Health (NSDUH) and Monitoring the Future, both of which have documented declining cigarette use and rising e-cigarette use among younger populations. However, this study extends prior work by examining the co-use dimension explicitly, revealing that the decline in cigarette use does not simply translate to less polysubstance involvement but rather to a restructuring of which products are combined with alcohol and cannabis. The inverted-U pattern of e-cigarette and alcohol co-use among youth is a novel contribution, potentially reflecting the impact of federal enforcement actions against flavored e-cigarettes and the Tobacco 21 legislation that took effect during the study period.
The Wave 5 spike in e-cigarette and cannabis co-use aligns temporally with expanding cannabis legalization and the rapid adoption of cannabis vaping devices, suggesting product-market convergence may be driving co-use trends in ways that merit further investigation.
Common Misreadings
The most likely overinterpretation is concluding that e-cigarettes are causing increased alcohol or cannabis use among young people. This study measures concurrent use within a 30-day window, not simultaneous use and not causal pathways. The observed co-use trends may reflect shared risk factors, cultural shifts in product preferences, or market availability rather than any pharmacological gateway effect. Equally important, readers should not interpret the declining youth e-cigarette co-use at Wave 6 as evidence that the problem is resolving on its own; the study period ends in 2021, and subsequent market changes, including the proliferation of disposable e-cigarettes, may have altered trajectories since then.
Bottom Line
This study provides robust descriptive evidence that polysubstance co-use patterns in the United States are restructuring along age lines, with e-cigarettes replacing cigarettes as the primary tobacco product combined with alcohol and cannabis among younger users. It does not establish health consequences of these new patterns or prove causation. For practice now, the key implication is that co-use screening must be age-stratified, product-specific, and updated to reflect the reality that vaping has become central to how younger patients engage with multiple substances.
Frequently Asked Questions
Does this study show that vaping leads to drinking or cannabis use?
No. The study measures whether people use these substances within the same 30-day period, not whether one causes the other. People who vape and drink may do so for entirely separate reasons, and shared risk factors such as age, social environment, and personality traits likely explain much of the overlap. Causal claims would require a fundamentally different study design.
Why did e-cigarette and alcohol co-use among teens rise and then fall during the study?
The study cannot definitively explain this pattern, but the timing aligns with federal enforcement actions against flavored e-cigarettes and the implementation of Tobacco 21 laws. These policy changes may have reduced youth access to e-cigarettes during the later waves of data collection, though other factors could also be involved.
Is combining e-cigarettes with alcohol or cannabis more dangerous than using any of these alone?
The health consequences of these specific co-use combinations are not well characterized yet. Research on cigarette and alcohol co-use shows clearly elevated risks for cancers and cardiovascular disease, but equivalent long-term data for e-cigarette-based co-use patterns simply do not exist. Clinicians generally advise that using multiple substances increases overall risk, but the precise magnitude of interaction effects for these newer combinations remains an active research question.
How was “co-use” defined in this study, and does it mean people used these substances at the same time?
Co-use was defined as using both a tobacco or nicotine product and alcohol or cannabis within the past 30 days. This does not mean the substances were used simultaneously or in the same session. Someone who vaped on weekdays and drank alcohol on weekends would be classified as a co-user. This is an important distinction because simultaneous use may carry different risks than use on separate occasions within the same month.
Should I be screened for polysubstance use even if I only use one substance regularly?
Yes, and this study reinforces why. Many people do not recognize occasional or social use of a second substance as clinically relevant, but co-use patterns can affect treatment approaches, medication interactions, and health risk profiles. If your clinician asks about multiple substances in the same conversation, they are following best practices supported by data like these. Being forthcoming about all substance use, even infrequent use, helps ensure you receive appropriate guidance.
References
- Population Assessment of Tobacco and Health (PATH) Study Public Use Files, Waves 4 through 6 (December 2016 to November 2021). National Institute on Drug Abuse and FDA Center for Tobacco Products. Available at: https://www.icpsr.umich.edu/web/NAHDAP/series/606
- Hyland A, Ambrose BK, Conway KP, et al. Design and methods of the Population Assessment of Tobacco and Health
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