French study: daily cannabis use raised the risk of trying other drugs 124-fold among teens
In a French cohort of 29,393 teenagers, daily cannabis users were 124 times more likely to initiate other illicit drugs than non-users, after adjusting for tobacco and alcohol.
Quick Facts
What This Study Found
Using a retrospective cohort of 29,393 French teenagers, researchers modeled all possible pathways from initial abstinence through cannabis initiation, daily cannabis use, and other illicit drug (OID) initiation using a Markov multi-state model.
The risk of initiating other illicit drugs was 21 times higher among cannabis experimenters and 124 times higher among daily cannabis users compared to non-users, after adjusting for tobacco and alcohol use. Tobacco and alcohol use also increased the risk of progressing to cannabis use.
The authors suggested OID experimentation could be a consequence of opportunity: once someone uses the most accessible illicit drug (cannabis), they gain access to social networks and markets where other drugs are available.
Key Numbers
29,393 teenagers. Cannabis experimenters: 21x higher OID risk. Daily cannabis users: 124x higher OID risk. Tobacco initiation HR=1.2, daily tobacco HR=2.6, drunkenness HR=2.8 for cannabis progression.
How They Did This
Retrospective cohort of 29,393 French teenagers. Markov multi-state model modeled all pathways from abstinence through cannabis stages to other drug initiation. Adjusted for tobacco and alcohol use as transition modifiers.
Why This Research Matters
The 124-fold increase for daily users was striking and provided quantitative support for stage-based drug use progression. The opportunity-based explanation (access to drug networks) offered a more nuanced view than simple pharmacological gateway theories.
The Bigger Picture
This study modeled the entire sequence of drug use progression, going beyond simply asking "does cannabis lead to other drugs?" to quantifying the risk at each stage. The dose-response relationship (experimenters vs daily users) strengthened the association.
What This Study Doesn't Tell Us
Retrospective self-report data. French teenager population may not generalize globally. The 124-fold increase, while large, may partly reflect selection effects (people who use cannabis daily are different from non-users in many ways). Cannot prove causation despite the multi-state modeling approach.
Questions This Raises
- ?Would delaying cannabis initiation reduce other drug use?
- ?Does the opportunity hypothesis mean regulated cannabis markets could reduce the gateway effect?
- ?Is the 124-fold increase an artifact of the population most likely to use any drug?
Trust & Context
- Key Stat:
- 124x higher risk of trying other drugs for daily cannabis users
- Evidence Grade:
- Large retrospective cohort with sophisticated multi-state modeling and adjustment for confounders. Strong for quantifying associations but cannot prove causation.
- Study Age:
- Published in 2012. The stage model of drug use progression continues to be debated and studied.
- Original Title:
- Cannabis use stages as predictors of subsequent initiation with other illicit drugs among French adolescents: use of a multi-state model.
- Published In:
- Addictive behaviors, 37(2), 160-6 (2012)
- Authors:
- Mayet, Aurélie(2), Legleye, Stéphane, Falissard, Bruno(2), Chau, Nearkasen
- Database ID:
- RTHC-00588
Evidence Hierarchy
Looks back at existing records to find patterns.
What do these levels mean? →Frequently Asked Questions
Does cannabis really lead to harder drugs?
This study found a strong dose-response association: cannabis experimenters were 21 times and daily users were 124 times more likely to try other illicit drugs. However, the authors emphasized opportunity (access to drug networks) rather than pharmacological causation as the likely explanation.
Could legal cannabis reduce the gateway effect?
If the opportunity hypothesis is correct (cannabis use provides access to markets where other drugs are available), then regulated cannabis markets that separate cannabis from other drug supply chains could theoretically reduce progression to other drugs. This is debated.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-00588APA
Mayet, Aurélie; Legleye, Stéphane; Falissard, Bruno; Chau, Nearkasen. (2012). Cannabis use stages as predictors of subsequent initiation with other illicit drugs among French adolescents: use of a multi-state model.. Addictive behaviors, 37(2), 160-6. https://doi.org/10.1016/j.addbeh.2011.09.012
MLA
Mayet, Aurélie, et al. "Cannabis use stages as predictors of subsequent initiation with other illicit drugs among French adolescents: use of a multi-state model.." Addictive behaviors, 2012. https://doi.org/10.1016/j.addbeh.2011.09.012
RethinkTHC
RethinkTHC Research Database. "Cannabis use stages as predictors of subsequent initiation w..." RTHC-00588. Retrieved from https://rethinkthc.com/research/mayet-2012-cannabis-use-stages-as
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.