Vaping Nicotine and Cannabis at the Same Time Led to More Vaping of Both

What the researchers found

On days with same-occasion co-vaping, participants reported the greatest intensity of both nicotine and cannabis vaping compared to all other patterns (single-substance vaping, same-day different-occasion co-vaping, or non-vaping days). Same-day different-occasion co-vaping also showed higher intensities than single-substance vaping.

Why it matters

Understanding which co-use patterns carry the most risk is important for targeted intervention. This study identifies same-occasion co-vaping as the highest-risk pattern, which could inform screening tools and cessation messaging for young adults.

The numbers in context

n=111; 30-day daily assessment; 2,522 total daily assessments; 84.7% reported co-vaping in past 30 days; 42.7% nicotine-only days; 9.7% cannabis-only days; 16.5% same-day different-occasion co-vaping; 16.9% same-occasion co-vaping.

How the study worked

Smartphone-based daily diary study collecting 30 consecutive days of vaping behavior from 111 California young adults (aged 18-29) who vaped at least 20 days per month. Generalized linear mixed-effects models examined day-level associations between vaping patterns and vaping intensity, controlling for covariates.

What this study cannot tell us

Self-reported daily diary data may be inaccurate, particularly for vaping frequency. California-only sample may not represent other regions. Correlational daily-level associations cannot establish causation. Cannot determine whether co-vaping causes higher intensity or higher-intensity vapers are more likely to co-vape.

How to read the evidence

Moderate: Novel daily diary design capturing real-time behavior with statistical modeling, though modest sample size and self-reported data are limitations.

When this study was published

Published in 2025 with 2023-2024 data.

The bigger picture

As nicotine and cannabis vaping devices become more similar and both substances are increasingly accessible to young adults, co-use patterns are likely to grow. This study provides the first daily-level evidence that temporal proximity of co-use matters for consumption intensity.

Questions still open

• What drives young adults to co-vape on the same occasion rather than separately? Does same-occasion co-vaping predict escalation to dependence faster than other patterns? Would interventions targeting same-occasion co-vaping reduce overall consumption?

Common questions

Read the original research

Vaping nicotine and cannabis on the same occasion is linked to increased vaping consumption among young adults: A smartphone-based daily diary study.

Drug and alcohol dependence, 266, 112517

Citation

Nguyen, Nhung; Keyhani, Salomeh; Marcus, Gregory M; Do, Vuong V; Halliday, Deanna M; Herbst, Ellen D; Ling, Pamela M. (2025). Vaping nicotine and cannabis on the same occasion is linked to increased vaping consumption among young adults: A smartphone-based daily diary study.. Drug and alcohol dependence, 266, 112517. https://doi.org/10.1016/j.drugalcdep.2024.112517

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