Young Women Who Used Cannabis and Tobacco at the Same Time Had Worse Cannabis Outcomes
Among young women who used both cannabis and tobacco, those who used them simultaneously (on the same occasion) were 1.6 times more likely to develop cannabis abuse than those who used them separately.
Quick Facts
What This Study Found
Using data from 3,427 young women, researchers distinguished between co-occurring use (using both substances in one's life) and simultaneous use (using cannabis and tobacco on the same occasion).
Regular cigarette smokers were 4.5-9.5 times more likely to also use cannabis and progress to cannabis abuse or dependence compared to non-smokers.
Among the 1,073 women who used both substances, those who used them simultaneously were 1.6 times more likely to meet criteria for DSM-IV cannabis abuse, even after controlling for early risk factors and prior cannabis use stages.
Twin analysis revealed that simultaneous use was not heritable (0% genetic influence) but was partly explained by shared environmental factors (31%), suggesting that peer groups and social contexts, rather than genetics, drive the behavior of combining these substances.
Key Numbers
3,427 women total. Regular smokers: 4.5-9.5x more likely to use cannabis. 1,073 co-occurring users. Simultaneous users: 1.6x more likely to have cannabis abuse (OR 1.6). Heritability of simultaneous use: 0%. Shared environment: 31%.
How They Did This
Cross-sectional analysis of 3,427 young adult women from a twin registry. Distinguished co-occurring from simultaneous cannabis-tobacco use. Logistic regression examined associations with cannabis outcomes. Twin modeling estimated genetic and environmental contributions to simultaneous use.
Why This Research Matters
This study identified simultaneous cannabis-tobacco use as a marker for more severe cannabis outcomes. The finding that this behavior is environmentally (not genetically) driven suggests it may be modifiable through peer-based or contextual interventions.
The Bigger Picture
The distinction between co-occurring and simultaneous substance use is clinically important. Simultaneous use may involve different motivations, social contexts, or pharmacological interactions than simply using both substances at different times.
What This Study Doesn't Tell Us
Cross-sectional design cannot establish causation. Only women were studied. Self-reported simultaneous use may be imprecise. The cannabis-tobacco interaction mechanism was not investigated.
Questions This Raises
- ?Does tobacco pharmacologically enhance cannabis's addictive properties when used simultaneously?
- ?Would interventions targeting the social contexts of simultaneous use reduce cannabis problems?
Trust & Context
- Key Stat:
- Simultaneous cannabis-tobacco use: 1.6x higher cannabis abuse risk, 0% heritable
- Evidence Grade:
- This is a well-designed twin study with a large sample, providing moderate evidence for the simultaneous use-cannabis outcome association and the environmental basis of this behavior.
- Study Age:
- Published in 2009. Research on cannabis-tobacco co-use has continued to identify it as a risk factor for worse outcomes.
- Original Title:
- Simultaneous cannabis and tobacco use and cannabis-related outcomes in young women.
- Published In:
- Drug and alcohol dependence, 101(1-2), 8-12 (2009)
- Authors:
- Agrawal, Arpana(39), Lynskey, Michael T(26), Madden, Pamela A F(15), Pergadia, Michele L, Bucholz, Kathleen K, Heath, Andrew C
- Database ID:
- RTHC-00341
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
What is the difference between co-occurring and simultaneous use?
Co-occurring means using both cannabis and tobacco in your life, perhaps on different days. Simultaneous means using them at the same time or on the same occasion. This study found that simultaneous use is specifically associated with worse cannabis outcomes.
Why does combining cannabis and tobacco matter?
Simultaneous use may change the pharmacological experience, reinforce use patterns through paired associations, or indicate a social context that promotes heavier use. Whatever the mechanism, it was linked to 1.6 times higher cannabis abuse risk.
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Cite This Study
https://rethinkthc.com/research/RTHC-00341APA
Agrawal, Arpana; Lynskey, Michael T; Madden, Pamela A F; Pergadia, Michele L; Bucholz, Kathleen K; Heath, Andrew C. (2009). Simultaneous cannabis and tobacco use and cannabis-related outcomes in young women.. Drug and alcohol dependence, 101(1-2), 8-12. https://doi.org/10.1016/j.drugalcdep.2008.10.019
MLA
Agrawal, Arpana, et al. "Simultaneous cannabis and tobacco use and cannabis-related outcomes in young women.." Drug and alcohol dependence, 2009. https://doi.org/10.1016/j.drugalcdep.2008.10.019
RethinkTHC
RethinkTHC Research Database. "Simultaneous cannabis and tobacco use and cannabis-related o..." RTHC-00341. Retrieved from https://rethinkthc.com/research/agrawal-2009-simultaneous-cannabis-and-tobacco
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.