What topics does this cannabis study cover?

This study covers research on: Addiction.

Teen substance co-use may drive heavier alcohol and nicotine use

Q: What did this research study find?

In **year 6**, adolescents used significantly more *nicotine* when it was co-used with alcohol or cannabis than when nicotine was used alone.

Q: Where was this research published?

Published in The Journal of adolescent health : official publication of the Society for Adolescent Medicine on August 7, 2026.

Co-use of Some Substances Associated With Higher Doses in Adolescents: Findings From the Adolescent Brain Cognitive Development Study.

The Journal of adolescent health : official publication of the Society for Adolescent Medicine • August 7, 2026 • Relevant

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AI Summary

This study examined how adolescents use alcohol, cannabis, and nicotine—either alone or on the same day as another substance—using data from six waves of the Adolescent Brain Cognitive Development study. The researchers compared average doses during single-substance use with doses during co-use, defined as using two substances on the same day.

In year 6, nicotine doses were significantly higher when nicotine was co-used with alcohol or cannabis, and alcohol doses were higher when alcohol was co-used with cannabis or nicotine. These nicotine patterns were similar in years 4 and 5. Cannabis doses, however, did not significantly differ between single use and co-use with alcohol or nicotine. The findings suggest that co-use—particularly involving alcohol and nicotine—may be associated with heavier use during adolescence, although the study does not establish that co-use directly causes higher dosing.

💡 Key Findings

In year 6, adolescents used significantly more nicotine when it was co-used with alcohol or cannabis than when nicotine was used alone.

High

80%

In year 6, average alcohol use was higher when alcohol was co-used with cannabis or nicotine compared with alcohol-only use.

High

80%

Average cannabis dose did not significantly differ between single use and co-use with alcohol or nicotine during the study years.

High

80%

The findings indicate that adolescent co-use, especially involving alcohol and nicotine, may be linked to higher average doses, but they do not prove that co-use causes heavier consumption.

Good

75%

📄 Original Abstract

Adolescence is a critical developmental period marked by heightened vulnerability to initiating substance use, with long-term implications for health and behavior. Nicotine, alcohol, and cannabis are the most commonly used substances among adolescents. Their use often co-occurs but few studies have described or quantified the patterns and doses of substance co-use in this vulnerable population. We used data from six waves of the Adolescent Brain Cognitive Development study. Substance use was measured through a web-based timeline followback interview, and outcomes are operationalized into substance use quantity (in standard units), single use, and co-use (use of two substances on the same day) of alcohol, cannabis, and nicotine. Group differences of average dose in standard units between single use and co-use for each substance class were analyzed using linear mixed-effects modeling in years 4-6. The average dose of nicotine was significantly higher when co-used with alcohol (4.32; 95% confidence interval [CI]: 2.55-6.09; p < .001) or when co-used with cannabis (4.41; 95% CI: 2.76-6.05; p < .001) in year 6; nicotine trends were similar in years four and five. In year 6, the average dose of alcohol was higher when co-used with cannabis (1.87; 95% CI: 0.37-3.36; p = .004) or co-used with nicotine (1.64; 95% CI: 0.06-3.22; p = .03) compared to single use of alcohol. The average dose of cannabis was not significantly different when used singularly or co-used with either alcohol or nicotine in our study years. During adolescence, the co-use of substances (namely alcohol and nicotine) may lead to higher average doses compared to single-substance use.

Paper Type

📄 Research

Publication

Journal: The Journal of adolescent health : official publication of the Society for Adolescent Medicine
Published: August 7, 2026
PMID: 42563619
DOI: 10.1016/j.jadohealth.2026.06.007

Authors (9)

Colbey Ricklefs Division of Adolescent and Young Adult Medicine, Department of Pediatrics, University of California, San Francisco, San Francisco, California; Division of Prevention Science, Department of Medicine, University of California, San Francisco, San Francisco, California. Electronic address: colbey.ricklefs@ucsf.edu.
Kristen E Kim Division of Adolescent and Young Adult Medicine, Department of Pediatrics, University of California, San Francisco, San Francisco, California.
Ari Thompson Division of Adolescent and Young Adult Medicine, Department of Pediatrics, University of California, San Francisco, San Francisco, California; School of Medicine, University of California, San Francisco, San Francisco, California.
Glenn-Milo Santos Division of Prevention Science, Department of Medicine, University of California, San Francisco, San Francisco, California; Department of Community Health Systems, School of Nursing, University of California, San Francisco, San Francisco, California.
Claire D Brindis Division of Adolescent and Young Adult Medicine, Department of Pediatrics, University of California, San Francisco, San Francisco, California; Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco, San Francisco, California.
+4 more authors