Using nationally representative PATH study data, researchers found e-cigarette and cannabis co-use increased among 15-34 year olds from 2016 to 2021 while traditional cigarette-cannabis co-use remained stable or declined.
Public health professionals, substance use researchers, and policymakers tracking evolving patterns of polysubstance use among youth and young adults.
E-cigarette + cannabis co-use rising among 15-34 year olds
What the researchers found
E-cigarette and alcohol co-use increased among young adults (18-34), possibly replacing cigarette-alcohol co-use which declined. E-cigarette and cannabis co-use increased at Wave 5 among those 15-34, though this increase lessened at Wave 6 for most groups except ages 25-34. Cigarette-cannabis co-use rates were generally stable or decreasing.
Why it matters
Co-use of multiple substances carries risks beyond single-product use. As the substance landscape shifts toward vaping, understanding how co-use patterns evolve across age groups helps target public health messaging and intervention.
The numbers in context
PATH Study Waves 4-6, ages 15+. Five age groups analyzed: 15-17, 18-24, 25-34, 35-64, 65+. E-cigarette and cannabis co-use increased at Wave 5 among those 15-17, 18-24, and 25-34. Cigarette-alcohol co-use declined among 18-24 and 25-34 year olds.
How the study worked
Longitudinal analysis of PATH Study Waves 4-6 (December 2016 to November 2021) including all participants age 15+. Changes in past 30-day co-use of cigarettes, e-cigarettes, and other tobacco products with alcohol and cannabis were examined, moderated by age group and controlling for demographics.
What this study cannot tell us
Self-reported data. Co-use defined as same 30-day period, not necessarily simultaneous use. Data ends November 2021, missing post-pandemic recovery period. Broad product categories may mask important variation.
How to read the evidence
Strong: nationally representative longitudinal data from the PATH study with multiple waves and age-stratified analysis.
When this study was published
Published 2026. Data from December 2016 to November 2021.
The bigger picture
This study captures a pivotal period when vaping rapidly gained popularity. The apparent substitution of e-cigarettes for traditional cigarettes in co-use patterns suggests the substance landscape is reshaping rather than simply expanding.
Questions still open
- Is the increase in e-cigarette and cannabis co-use driven by shared vaping technology? Do co-use patterns carry different health risks than single-substance use? Have post-2021 trends continued or reversed?
Common questions
Are young people using e-cigarettes and cannabis together more often?
Is vaping replacing smoking in substance co-use patterns?
Read the original research
Longitudinal trends in the past 30-day co-use of nicotine/tobacco, alcohol, and cannabis among youth and adults in the PATH study.
Addictive behaviors, 176, 108633
Citation
Sokolovsky, Alexander W; Micalizzi, Lauren; Murphy, Cara M. (2026). Longitudinal trends in the past 30-day co-use of nicotine/tobacco, alcohol, and cannabis among youth and adults in the PATH study.. Addictive behaviors, 176, 108633. https://doi.org/10.1016/j.addbeh.2026.108633
Explore the wider topic
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