Evidence That Cannabis Laws Reduce Opioid Problems Is Still Inconclusive
A review of 21 studies examining whether cannabis laws affect opioid outcomes found largely inconclusive results, identifying six major research challenges that limit current evidence.
Quick Facts
What This Study Found
Across 21 U.S. studies, results on whether cannabis laws reduce opioid prescribing, use, or mortality were largely inconclusive. Six key challenges were identified: inability to measure direct substitution, lack of individual-level longitudinal data, difficulty separating cannabis law effects from other policies, staggered implementation issues, limited consideration of specific law provisions, and insufficient data triangulation.
Key Numbers
21 studies reviewed; published 2014-2021; 6 research challenges identified; outcomes examined included opioid prescribing, use, use disorder, service utilization, and mortality; results largely inconclusive.
How They Did This
Narrative review of 21 U.S.-based studies published 2014-2021 examining associations between state medical and recreational cannabis laws and opioid-related outcomes.
Why This Research Matters
The popular narrative that cannabis legalization reduces opioid problems is not well supported by current evidence. Understanding the specific research gaps is essential before making policy claims about cannabis as an opioid substitute.
The Bigger Picture
While there are theoretical reasons to expect cannabis laws could affect opioid outcomes, the current evidence base cannot reliably confirm or deny this relationship, and premature policy conclusions could be harmful.
What This Study Doesn't Tell Us
Narrative rather than systematic review; limited to U.S. studies; rapidly evolving policy landscape means findings may become outdated; does not include studies published after 2021.
Questions This Raises
- ?Would individual-level longitudinal studies using multiple data sources provide clearer answers?
- ?Are specific cannabis law provisions (like allowing pain as a qualifying condition) more important than simple legal vs. illegal distinctions?
Trust & Context
- Key Stat:
- 21 studies examined cannabis laws and opioid outcomes with largely inconclusive results
- Evidence Grade:
- Narrative review identifying consistent methodological limitations across studies, providing moderate confidence in the assessment of evidence gaps.
- Study Age:
- Studies published 2014-2021.
- Original Title:
- The state of the evidence on the association between state cannabis laws and opioid-related outcomes: A review.
- Published In:
- Current addiction reports, 8(4), 538-545 (2021)
- Authors:
- Tormohlen, Kayla N(3), Bicket, Mark C(3), White, Sarah, Barry, Colleen L, Stuart, Elizabeth A, Rutkow, Lainie, McGinty, Emma E
- Database ID:
- RTHC-03582
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Does cannabis legalization reduce opioid deaths?
The current evidence is inconclusive. While some studies suggest potential benefits, the review identified six major research challenges that prevent definitive conclusions about whether cannabis laws actually reduce opioid-related harms.
Why is the evidence so unclear?
Key challenges include the inability to directly measure whether people substitute cannabis for opioids, lack of individual-level data tracking people over time, and difficulty separating the effects of cannabis laws from other concurrent policy changes.
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Cite This Study
https://rethinkthc.com/research/RTHC-03582APA
Tormohlen, Kayla N; Bicket, Mark C; White, Sarah; Barry, Colleen L; Stuart, Elizabeth A; Rutkow, Lainie; McGinty, Emma E. (2021). The state of the evidence on the association between state cannabis laws and opioid-related outcomes: A review.. Current addiction reports, 8(4), 538-545. https://doi.org/10.1007/s40429-021-00397-1
MLA
Tormohlen, Kayla N, et al. "The state of the evidence on the association between state cannabis laws and opioid-related outcomes: A review.." Current addiction reports, 2021. https://doi.org/10.1007/s40429-021-00397-1
RethinkTHC
RethinkTHC Research Database. "The state of the evidence on the association between state c..." RTHC-03582. Retrieved from https://rethinkthc.com/research/tormohlen-2021-the-state-of-the
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.