International forskning

The Cannabis-Dependent Relationship Between Methadone Treatment Dose and Illicit Opioid Use in a Community-Based Cohort of People Who Use Drugs

Stephanie Lake 1 2 3, Thomas Kerr 1 4, Jane Buxton 5, Zach Walsh 6, Ziva D Cooper 2 3, M Eugenia Socías 1 4, Nadia Fairbairn 1 4, Kanna Hayashi 1 7, M-J Milloy 1 4

  • 1British Columbia Centre on Substance Use, Vancouver, Canada.
  • 2UCLA Cannabis Research Initiative, Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, California, USA.
  • 3Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California, USA.
  • 4Division of Social Medicine, Department of Medicine, University of British Columbia, St. Paul’s Hospital, Vancouver, Canada.
  • 5School of Population and Public Health, University of British Columbia, Vancouver, Canada.
  • 6Department of Psychology, University of British Columbia, Kelowna, Canada.
  • 7Faculty of Health Sciences, Simon Fraser University, Burnaby, Canada.


Background: Methadone maintenance treatment (MMT) is an effective treatment for opioid use disorder. However, subtherapeutic dosing may lead to continued opioid use by failing to suppress opioid withdrawal and craving. Preclinical and pilot experimental research suggests that cannabinoids may reduce opioid withdrawal and craving. We sought to test whether the association between low methadone dose and illicit opioid use differs according to concurrent cannabis use patterns. Methods: Data for this study were derived from two community-recruited cohorts of people (≥18 years old) who use illicit drugs in Vancouver, Canada. We used generalized estimating equations to estimate the adjusted association between lower daily MMT dose (<90 mg/day) and daily illicit opioid use, testing for interaction between dose and daily cannabis use. Results: Between December 2005 and December 2018, 1389 participants reported MMT enrolment and were included in the study. We observed a significant interaction (p<0.01) between daily cannabis and lower MMT dose on concurrent daily illicit opioid use: lower MMT doses increased the odds of daily illicit opioid use by 86% (adjusted odds ratio [AOR]=1.86, 95% confidence interval [CI]=1.61-2.16) during periods of no or low-frequency cannabis use and by 30% during periods of daily cannabis use (AOR=1.30, 95% CI=1.01-1.67). Discussion: This study provides preliminary observational evidence that cannabis may mitigate some of the negative effects of subtherapeutic MMT dosing, guiding future clinical investigations into the safety and efficacy of cannabis and cannabinoids as adjunct treatment for MMT.

Keywords: cannabis; cohort study; methadone; opioid agonist treatment; opioid use disorder; opioids.