Adolescents who started using marijuana before age 13 had higher odds of using other substances and engaging in violence, with gambling status modifying several of these relationships.
adolescent health researchers, school prevention specialists, substance use counselors
What the researchers found
Early marijuana use (before age 13) was associated with higher odds of cigarette smoking, alcohol use, heavy drinking, lifetime cocaine use, e-cigarette use, and physical fighting compared to no use. Among gambling adolescents, early use was specifically linked to greater odds of prescription opiate misuse and any substance use. Gambling status modified associations with opiate misuse, substance use, school bullying, and forced sexual intercourse.
Why it matters
Early initiation of any substance is a well-known risk factor, but the interaction with gambling behavior suggests that adolescents who engage in multiple risk behaviors may face compounding vulnerabilities.
The numbers in context
2,015 adolescents from 2019 YRBS. Early MU linked to higher odds of cigarette smoking, alcohol, heavy drinking, cocaine, e-cigarettes, and fighting. Gambling adolescents with early MU had greater odds of prescription opiate misuse. Gambling status moderated associations with opiate misuse, substance use, bullying, and forced sexual intercourse.
How the study worked
Analysis of 2019 Youth Risk Behavior Surveillance survey data (n=2,015) examining relationships between early (<13 years), later (>=13 years), and no marijuana use with substance use and violence, stratified by gambling status. Adjusted multivariate logistic regression models.
What this study cannot tell us
Cross-sectional survey design limits causal conclusions. Self-reported data from adolescents. YRBS is school-based, missing out-of-school youth. Gambling measure not standardized. Cannot determine directionality between marijuana use and other behaviors.
How to read the evidence
National survey data with adequate sample and multivariate modeling, but cross-sectional design and self-report limit to moderate.
When this study was published
Data from the 2019 Youth Risk Behavior Surveillance survey.
The bigger picture
This study highlights that early marijuana use is not an isolated risk factor but part of a cluster of risky behaviors. The gambling interaction suggests that some adolescents may have a general vulnerability to multiple risk behaviors rather than substance-specific risk.
Questions still open
- What drives the specific interaction between gambling and early marijuana use?
- Would prevention programs targeting multiple risk behaviors be more effective than substance-specific programs?
Common questions
Why is starting marijuana before age 13 particularly risky?
Does gambling make marijuana use worse?
Read the original research
The Relationships of Early Use of Marijuana With Substance Use and Violence in Adolescent Gamblers and Non-Gamblers.
Journal of the Korean Academy of Child and Adolescent Psychiatry, 36(3), 89-105
Citation
Sirek, Greta; Stefanovics, Elina A; Iyer, Rasika; Potenza, Marc N; Zhai, Zu Wei. (2025). The Relationships of Early Use of Marijuana With Substance Use and Violence in Adolescent Gamblers and Non-Gamblers.. Journal of the Korean Academy of Child and Adolescent Psychiatry, 36(3), 89-105. https://doi.org/10.5765/jkacap.250012
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