Among 80,018 Colombian students, marijuana users showed higher rates of aggression and victimization than non-users, but polydrug use and the sequence of drug initiation were stronger predictors than marijuana use alone.
Prevention researchers, school-based health professionals, and policymakers in Latin American countries navigating cannabis regulation.
What the researchers found
Exclusive marijuana users had higher odds of aggression compared to non-drug users, but lower odds than polydrug users. Adolescents who initiated marijuana before other drugs showed greater odds of aggression than exclusive marijuana users, and those who used marijuana after other drugs showed even higher rates, suggesting that polydrug involvement and initiation sequence matter more than marijuana alone.
Why it matters
Most research on cannabis and aggression uses simple user versus non-user comparisons. This study shows that the relationship is far more nuanced: the order of drug initiation and number of substances used change the picture dramatically, challenging simplistic causal claims.
The numbers in context
80,018 students in grades 7-11. Non-drug users had lowest aggression and victimization rates. Multiple-drug users had the highest. Exclusive marijuana users showed increased odds of aggression vs. non-users, but initial and subsequent users showed greater odds. Polydrug involvement and initiation order significantly modified associations.
How the study worked
Secondary analysis of nationally representative 2016 cross-sectional data from 80,018 Colombian students in grades 7-11. Participants categorized into marijuana-use groups (exclusive, initial, subsequent) and non-marijuana groups (no drug, one drug, multiple drugs). Logistic regression controlled for sex, age, parental education, and grade repetition.
What this study cannot tell us
Cross-sectional design cannot establish causation. Self-reported aggression and drug use subject to reporting biases. 2016 Colombian context may differ from other countries. Cannot control for all confounders like mental health conditions, family violence, or socioeconomic factors beyond parental education.
How to read the evidence
Very large nationally representative sample with nuanced categorization of drug use patterns, but cross-sectional design and self-reported data limit causal interpretation.
When this study was published
Published 2025, using 2016 Colombian survey data.
The bigger picture
The finding that initiation sequence matters suggests that marijuana's association with aggression may partly reflect broader patterns of risk-taking behavior rather than a pharmacological effect of cannabis itself. This has implications for prevention: targeting the underlying risk factors may be more effective than focusing on a single substance.
Questions still open
- Whether the initiation-sequence finding reflects shared risk factors or a genuine escalation pathway
- How cultural and regulatory context in Colombia affects the relationship between marijuana and aggression compared to other countries
Common questions
Does marijuana cause aggression?
Why does the order of drug initiation matter?
Read the original research
Evaluating the relationship between marijuana use, aggressive behaviors, and victimization: an epidemiological study in colombian adolescents.
International journal of adolescent medicine and health, 37(1), 1-9
Citation
Scoppetta, Orlando; Cardozo, Francisco; Brown, Eric C; Morales, Vanessa. (2025). Evaluating the relationship between marijuana use, aggressive behaviors, and victimization: an epidemiological study in colombian adolescents.. International journal of adolescent medicine and health, 37(1), 1-9. https://doi.org/10.1515/ijamh-2024-0167
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