Cannabis and Alcohol Use Disorder: What Canadian Research Shows
Last Updated: February 2026 | Reading Time: 5 minutes
Managed Alcohol Programs (MAPs) are a harm reduction intervention designed for individuals experiencing severe alcohol use disorder alongside housing instability. Rather than requiring abstinence as a condition of care, MAPs provide a regulated supply of alcohol to reduce harms from non-beverage alcohol consumption, withdrawal, and unsafe drinking patterns. A growing body of peer-reviewed research has examined what happens when participants in these programs are also given access to medical cannabis — specifically, whether cannabis substitution reduces alcohol consumption.
This article reviews the current Canadian evidence base. Flora Initiative operates under High Hopes Research Society, a federally-licensed nonprofit that served as the community partner and program operator in the Vancouver component of the Canadian Managed Alcohol Program Study (CMAPS), a multi-site evaluation funded by Health Canada. The Ottawa findings from that study are now published in the International Journal of Drug Policy (2026).
The Ottawa Findings: Quantitative Evidence
The most methodologically rigorous study available is a 2026 paper by Goulet-Stock, Hacksel, Scandiuzzi, Boyd, Pauly & Stockwell, published open-access in the International Journal of Drug Policy (Vol. 147: 105083). The study examined cannabis substitution within an Ottawa MAP over two years, with N=35 participants.
The final hierarchical mixed-effects model found a substitution effect: participants who used more cannabis on average also consumed less alcohol overall. Specifically, each additional 0.4-gram pre-rolled joint consumed — approximately 15.2 standard THC units or 76 mg THC — was associated with an estimated 2.43 fewer mean daily standard drinks.
Two additional findings from this study deserve attention. First, within-person cannabis use was not a significant predictor: short-term, day-to-day fluctuations in cannabis consumption were not associated with concurrent changes in alcohol use. The substitution effect operated through stable individual patterns over time, not through acute trade-offs. Second, alcohol use declined over time as an independent trend, separate from the cannabis substitution effect.
Pre-Implementation Evidence: How Feasible Was This?
Before the Ottawa and Vancouver pilots ran, CMAPS researchers conducted a multi-site feasibility study across six Canadian MAPs to assess the viability of cannabis substitution programming. Pauly, Brown, Chow, Wettlaufer, Graham, Urbanoski et al. (2021), published in Harm Reduction Journal (18: 65), documented the results.
Among MAP participants surveyed, 84% expressed willingness to participate in a cannabis substitution program. More significantly, over 63% of enrolled MAP clients were already using cannabis to substitute for alcohol at baseline — before any formal program was in place. The feasibility study also identified what implementation would require: peer support infrastructure, a sustainable, regulated supply, and stable funding. These are the elements the High Hopes Vancouver program subsequently provided.
Community Knowledge Translation: Lived Experience Informing Design
A 2023 knowledge translation paper by Bailey, Harps, Belcher, Williams, Amos, Graham, Goulet-Stock et al., published in the International Journal of Drug Policy (DOI: 10.1016/j.drugpo.2023.104244), documents how the CMAPS, EIDGE, and SOLID Victoria collaboration drew on the lived experience of illicit drinkers — people surviving on non-beverage alcohol — to co-create the educational resources that MAP sites needed to implement cannabis substitution. No such resources existed before this collaboration. The paper establishes how community knowledge was treated as equivalent to clinical and methodological expertise in producing materials that participants and staff could actually use.
This is relevant for clinical and institutional audiences because it addresses a practical program design question: how do you produce guidance materials for a population for whom no established clinical resources exist? The answer the research documents is that lived experience involvement is not incidental to this process — it is what makes the resources accurate and trusted.
What the Research Does Not Show
The Goulet-Stock et al. (2026) findings are from a program serving people with severe alcohol use disorder and housing instability. The substitution effect documented in that population — 2.43 fewer standard drinks per additional joint — is a finding from that specific setting and that specific model of care. It does not establish that any medical cannabis product will produce equivalent results in other settings or populations.
The substitution effect is also not a uniform outcome across participants. Internal evaluation data from the Vancouver High Hopes program (not yet peer-reviewed) indicate that most participants experienced some level of change in alcohol consumption, but with considerable individual variation. These are real-world outcomes in a complex population, not controlled trial results.
Significance for Institutional and Clinical Audiences
The Goulet-Stock et al. (2026) paper is, to date, the highest-quality quantitative study of cannabis substitution within a formal Canadian harm reduction program. It is published in a major peer-reviewed journal, uses hierarchical mixed-effects modelling, draws on two years of longitudinal data, and produces a specific, interpretable effect size.
For institutions operating or considering MAP services, for healthcare programs serving populations with severe AUD, or for researchers examining cannabis substitution as a harm reduction modality, this paper represents the current Canadian evidence benchmark.
This article summarizes published peer-reviewed research for informational purposes. It does not constitute medical advice. Medical cannabis requires authorization from a qualified healthcare provider. The research cited represents the findings of independent investigators and does not constitute a health claim about any specific product.
References
- Bailey, Harps, Belcher, Williams, Amos, Graham, Goulet-Stock et al. (2023). International Journal of Drug Policy, 122: 104244. DOI: 10.1016/j.drugpo.2023.104244
- Goulet-Stock, Hacksel, Scandiuzzi, Boyd, Pauly & Stockwell (2026). International Journal of Drug Policy, 147: 105083. DOI: 10.1016/j.drugpo.2025.105083
- Pauly, Brown, Chow, Wettlaufer, Graham, Urbanoski et al. (2021). Harm Reduction Journal, 18: 65. DOI: 10.1186/s12954-021-00512-5