Does marijuana legalization reduce opioid abuse? Evidence is mixed.
Eight of ten studies found associations between marijuana decriminalization and reduced opioid use, but one cohort study found increased adverse opioid outcomes, and the overall evidence is limited by ecological study designs.
Quick Facts
What This Study Found
Of 10 studies meeting inclusion criteria (3 cross-sectional, 6 ecological, 1 retrospective cohort), 8 found associations between marijuana decriminalization policies and reduced prescription opioid use. One study was inconclusive, and the retrospective cohort study reported an increase in adverse opioid-related outcomes. The ecological designs use aggregate data and cannot establish that the same individuals used cannabis instead of opioids.
Key Numbers
10 studies met inclusion criteria. 8 found association between marijuana policies and reduced opioid use. 1 inconclusive. 1 found increased adverse outcomes. Study types: 3 cross-sectional, 6 ecological, 1 retrospective cohort.
How They Did This
Clinical inquiry (Clin-IQ) searching Ovid MEDLINE, MEDLINE In-Process, and Embase for population-based studies from January 2012 through December 2018 examining the relationship between marijuana decriminalization and opioid-related outcomes.
Why This Research Matters
The opioid crisis has driven interest in cannabis as a potential substitute for opioid pain management. Understanding whether this population-level relationship holds is critical for policy decisions.
The Bigger Picture
The one cohort study that tracked individuals (rather than aggregate state-level data) found the opposite result, which highlights the danger of making individual-level conclusions from state-level data.
What This Study Doesn't Tell Us
Mostly ecological studies using aggregate data. Cannot determine individual substitution behavior. Confounded by other policy changes occurring simultaneously. Search limited to one database family.
Questions This Raises
- ?Does individual-level cannabis substitution for opioids occur, or are the ecological associations driven by other factors?
- ?Do specific cannabis access policies (dispensary proximity, product types) matter more than legalization status?
Trust & Context
- Key Stat:
- 8 of 10 studies found reduced opioid use in legal states
- Evidence Grade:
- Systematic search with clear criteria, but underlying studies are mostly ecological with inherent limitations.
- Study Age:
- 2019 review of studies from 2012-2018.
- Original Title:
- Is There Less Opioid Abuse in States Where Marijuana Has Been Decriminalized, Either for Medicinal or Recreational Use? A Clin-IQ.
- Published In:
- Journal of patient-centered research and reviews, 6(4), 267-273 (2019)
- Authors:
- Wendelboe, Aaron M, Mathew, Richard, Chongsuwat, Tana, Rainwater, Elizabeth, Wendelboe, Mark A, Wickersham, Elizabeth, Chou, Ann F
- Database ID:
- RTHC-02345
Evidence Hierarchy
Analyzes all available research on a topic using a structured method.
What do these levels mean? →Frequently Asked Questions
Does legalizing marijuana reduce opioid use?
Eight of ten studies found associations between marijuana legalization and reduced opioid use at the population level, but most used aggregate state data rather than tracking individuals. The one study that tracked individuals found the opposite result.
Can cannabis replace opioids for pain?
Population-level data suggest an association between cannabis access and lower opioid use, but whether individuals are actually substituting cannabis for opioids remains unclear from the available evidence.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-02345APA
Wendelboe, Aaron M; Mathew, Richard; Chongsuwat, Tana; Rainwater, Elizabeth; Wendelboe, Mark A; Wickersham, Elizabeth; Chou, Ann F. (2019). Is There Less Opioid Abuse in States Where Marijuana Has Been Decriminalized, Either for Medicinal or Recreational Use? A Clin-IQ.. Journal of patient-centered research and reviews, 6(4), 267-273. https://doi.org/10.17294/2330-0698.1704
MLA
Wendelboe, Aaron M, et al. "Is There Less Opioid Abuse in States Where Marijuana Has Been Decriminalized, Either for Medicinal or Recreational Use? A Clin-IQ.." Journal of patient-centered research and reviews, 2019. https://doi.org/10.17294/2330-0698.1704
RethinkTHC
RethinkTHC Research Database. "Is There Less Opioid Abuse in States Where Marijuana Has Bee..." RTHC-02345. Retrieved from https://rethinkthc.com/research/wendelboe-2019-is-there-less-opioid
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.