One in four high-risk drug users in Vancouver reported using cannabis to reduce harm from other substances
Among marginalized people who use drugs in Vancouver, approximately 25% reported using cannabis as a harm reduction strategy at least once during the study period, most commonly to substitute for stimulants (50%) and illicit opioids (31%).
Quick Facts
What This Study Found
About 1 in 4 participants used cannabis for harm reduction during the study period. The most common reasons were substituting for stimulants (50%) and substituting for illicit opioids (31%). Other reasons included treating withdrawal and coming down off other drugs.
Key Numbers
~25% reported cannabis for harm reduction at least once; 50% for stimulant substitution; 31% for opioid substitution; study period June 2016 to May 2018
How They Did This
Data drawn from three prospective cohort studies of marginalized people who use drugs in Vancouver, Canada, from June 2016 to May 2018. Participants reported recent cannabis use and their intentions for using cannabis, including substitution for other substances.
Why This Research Matters
During an overdose crisis that has killed thousands in British Columbia, understanding how people at highest risk are already using cannabis to manage their drug use provides ground-level data that could inform future harm reduction interventions.
The Bigger Picture
People who use drugs are already employing cannabis as a self-directed harm reduction tool. Whether this strategy actually reduces overdose risk and other harms remains an important research question with potential implications for drug policy.
What This Study Doesn't Tell Us
Self-reported data from marginalized populations in one Canadian city. No comparison group. Cannot determine whether cannabis substitution actually reduced harm. Potential selection bias.
Questions This Raises
- ?Does cannabis substitution actually reduce overdose risk?
- ?Would formalized cannabis-based harm reduction programs be effective?
- ?What barriers exist to studying cannabis as a harm reduction tool?
- ?How do these patterns differ across demographic groups?
Trust & Context
- Key Stat:
- 25% used cannabis for harm reduction; 50% to substitute for stimulants
- Evidence Grade:
- Prospective cohort data from three established studies, but self-reported outcomes and single-city setting limit conclusions.
- Study Age:
- Published in 2021 using data from 2016-2018.
- Original Title:
- Use of Cannabis for Harm Reduction Among People at High Risk for Overdose in Vancouver, Canada (2016-2018).
- Published In:
- American journal of public health, 111(5), 969-972 (2021)
- Authors:
- Mok, Janice(2), Milloy, M-J(17), Grant, Cameron(2), Lake, Stephanie, DeBeck, Kora, Hayashi, Kanna, Socías, M Eugenia
- Database ID:
- RTHC-03353
Evidence Hierarchy
Enrolls participants and follows them forward in time.
What do these levels mean? →Frequently Asked Questions
What substances are people replacing with cannabis?
The most common substitutions were for stimulants (50% of those using cannabis for harm reduction) and illicit opioids (31%). Others used cannabis for treating withdrawal or coming down off other drugs.
Does substituting cannabis for opioids actually prevent overdose?
This study documented the practice but did not measure whether it actually reduced overdose risk. That remains an important unanswered question.
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Cite This Study
https://rethinkthc.com/research/RTHC-03353APA
Mok, Janice; Milloy, M-J; Grant, Cameron; Lake, Stephanie; DeBeck, Kora; Hayashi, Kanna; Socías, M Eugenia. (2021). Use of Cannabis for Harm Reduction Among People at High Risk for Overdose in Vancouver, Canada (2016-2018).. American journal of public health, 111(5), 969-972. https://doi.org/10.2105/AJPH.2021.306168
MLA
Mok, Janice, et al. "Use of Cannabis for Harm Reduction Among People at High Risk for Overdose in Vancouver, Canada (2016-2018).." American journal of public health, 2021. https://doi.org/10.2105/AJPH.2021.306168
RethinkTHC
RethinkTHC Research Database. "Use of Cannabis for Harm Reduction Among People at High Risk..." RTHC-03353. Retrieved from https://rethinkthc.com/research/mok-2021-use-of-cannabis-for
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.