Interventions for tobacco-cannabis co-users showed weak effects on cessation but some reduction in cannabis use
A systematic review and meta-analysis found that interventions for tobacco-cannabis co-users showed weak evidence for cannabis cessation and no clear effect on tobacco cessation, though cannabis use reduction was observed.
Quick Facts
What This Study Found
Meta-analysis of 11 RCTs (up to 1,117 participants) showed weak evidence for cannabis cessation (RR=1.48, CrI 0.92-2.49) and no clear effect on tobacco cessation (RR=1.10, CrI 0.68-1.87). Multi-substance interventions appeared more effective for cannabis cessation than cannabis-only interventions (RR=2.19 vs. 1.39). A significant effect was found for cannabis reduction but not tobacco reduction.
Key Numbers
20 studies included. 12 RCTs and 8 uncontrolled studies. Up to 1,117 participants in meta-analysis. Cannabis cessation RR=1.48. Tobacco cessation RR=1.10. Multi-substance interventions for cannabis cessation: RR=2.19.
How They Did This
Systematic review with Bayesian meta-analysis using informative priors. Five databases searched. 20 studies included (12 RCTs, 8 uncontrolled). Outcomes: cessation and reduction of both tobacco and cannabis.
Why This Research Matters
Tobacco and cannabis are frequently co-used, and quitting one may be harder when still using the other. This review highlights that current interventions have limited effectiveness for co-users, signaling a need for better-designed dual-substance programs.
The Bigger Picture
As cannabis and tobacco co-use becomes better recognized as a clinical problem, developing effective interventions that address both substances simultaneously could improve outcomes for a large population of dual users.
What This Study Doesn't Tell Us
Most included studies had small samples. Cannabis use measurement was not standardized across studies. Bayesian approach relies on prior assumptions. Moderate quality of evidence overall.
Questions This Raises
- ?Why are multi-substance interventions better for cannabis but not tobacco cessation?
- ?Would tailored co-use interventions that address the specific interaction between tobacco and cannabis be more effective?
- ?How should success be measured in co-users?
Trust & Context
- Key Stat:
- Multi-substance interventions doubled cannabis cessation odds (RR=2.19)
- Evidence Grade:
- Systematic review with Bayesian meta-analysis of RCTs. Moderate quality evidence limited by small studies and unstandardized cannabis measurement.
- Study Age:
- 2020 systematic review. First Bayesian meta-analysis specifically examining interventions for tobacco-cannabis co-users.
- Original Title:
- A systematic review and Bayesian meta-analysis of interventions which target or assess co-use of tobacco and cannabis in single- or multi-substance interventions.
- Published In:
- Addiction (Abingdon, England), 115(10), 1800-1814 (2020)
- Authors:
- Walsh, Hannah(2), McNeill, Ann(4), Purssell, Edward, Duaso, Maria
- Database ID:
- RTHC-02902
Evidence Hierarchy
Analyzes all available research on a topic using a structured method.
What do these levels mean? →Frequently Asked Questions
Is it harder to quit tobacco if you also use cannabis?
This review found that current cessation interventions have limited effectiveness for people who use both substances, suggesting co-use may complicate quitting either one.
Should co-users try to quit both at once?
The review found that interventions targeting both substances simultaneously appeared more effective for cannabis cessation than single-substance approaches, though evidence remains limited.
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Cite This Study
https://rethinkthc.com/research/RTHC-02902APA
Walsh, Hannah; McNeill, Ann; Purssell, Edward; Duaso, Maria. (2020). A systematic review and Bayesian meta-analysis of interventions which target or assess co-use of tobacco and cannabis in single- or multi-substance interventions.. Addiction (Abingdon, England), 115(10), 1800-1814. https://doi.org/10.1111/add.14993
MLA
Walsh, Hannah, et al. "A systematic review and Bayesian meta-analysis of interventions which target or assess co-use of tobacco and cannabis in single- or multi-substance interventions.." Addiction (Abingdon, 2020. https://doi.org/10.1111/add.14993
RethinkTHC
RethinkTHC Research Database. "A systematic review and Bayesian meta-analysis of interventi..." RTHC-02902. Retrieved from https://rethinkthc.com/research/walsh-2020-a-systematic-review-and
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.