UCSD Study: Girls Overtake Boys in Adolescent Substance Use After Age 13, With Nicotine-Cannabis Co-Use Most Common

27 Jul UCSD Study: Girls Overtake Boys in Adolescent Substance Use After Age 13, With Nicotine-Cannabis Co-Use Most Common

Dr. Ryan Sullivan PhD

MedicalResearch.com: What is the background for this study?

Dr. Sullivan: Adolescence is a critical period for brain development and a time when many young people begin experimenting with alcohol, cannabis, nicotine and other substances. Understanding when substance use begins, how it changes as young people get older, and which substances are most commonly used together can help researchers identify opportunities for prevention and better understand how early substance use may relate to later health outcomes. This study used data from the Adolescent Brain Cognitive Development (ABCD) Study, one of the largest longitudinal studies of youth in the United States, to provide an updated picture of substance use patterns from late childhood through mid-adolescence. Related MedicalResearch.com research has also found that cognitive brain circuits are altered in youth with significant cannabis use — underlining why tracking when and how adolescents begin using substances matters for understanding long-term neurodevelopmental outcomes.

MedicalResearch.com: What are the main findings?

Dr. Sullivan: The study found that substance use increased steadily as participants moved through adolescence. By age 16, 38% of participants reported having used at least one substance during their lifetime. Alcohol, cannabis and nicotine were the substances most commonly reported.

The researchers also identified differences by sex. Boys reported higher rates of substance use before age 12, but beginning around age 13, girls reported higher rates of alcohol, cannabis and nicotine use, with the largest differences seen for nicotine. Polysubstance use — using two or more substances — was also relatively common, with nearly 15% of participants reporting it during the study. The most common combination was nicotine and cannabis, and girls reported higher rates of polysubstance use after age 13, particularly combinations involving nicotine.

Importantly, estimates adjusted to better reflect the U.S. population were very similar to the study’s unadjusted estimates, suggesting that the ABCD cohort provides a useful representation of national patterns of adolescent substance use.

MedicalResearch.com: What should readers take away from your report?

Dr. Sullivan: The key takeaway is that substance use becomes increasingly common as young people move through adolescence, highlighting the importance of prevention and early intervention before or during the early teen years. The findings also show that substance use does not follow the same pattern for everyone. In particular, the shift toward higher rates of use among girls beginning around age 13 and the prevalence of nicotine-cannabis co-use point to the need for prevention strategies that account for differences in age, sex and patterns of substance use.

These findings also provide an important national benchmark for future research. By establishing when substance use emerges and how patterns evolve during adolescence, researchers can better investigate how substance use may intersect with brain development, mental health and other long-term outcomes.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Dr. Sullivan: It will be important to investigate why substance use patterns diverge between boys and girls around age 13 and to identify the factors that contribute to higher rates of use among girls during later adolescence. Additional research should examine the factors associated with polysubstance use, particularly nicotine and cannabis co-use, and determine whether using multiple substances is associated with different developmental or health outcomes than using a single substance. Future studies could also explore how family environment, peer relationships, mental health, social conditions and changing perceptions of substance-related risks influence when and how adolescents begin using substances.

MedicalResearch.com: Is there anything else you would like to add? Any disclosures?

Dr. Sullivan: One important point is that these findings should not be interpreted to mean that most adolescents use substances. The study found that substance use increases with age, but the majority of young people in the cohort had not reported using substances by age 16. The value of this research is in identifying when use becomes more common and the specific patterns that emerge, so that prevention efforts can be targeted at the times and populations when they may have the greatest impact.

Disclosures: The study was funded by the National Institute on Drug Abuse (NIDA) through National Institutes of Health awards DA064409, DA062011, DA050779, DA054980 and DA062432. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Citation: Sullivan RM, Wallace AL, Shankula CA, et al. Substance use patterns from late childhood to mid-adolescence: Updates on the Adolescent Brain Cognitive Development Study. Drug and Alcohol Dependence Reports. 2026;20:100463. https://doi.org/10.1016/j.dadr.2026.100463

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Last Updated on July 27, 2026 by Marie Benz MD FAAD