Medical cannabis improved quality of life and reduced opioid use in people with substance use disorder
In a UK registry of 34 patients with substance use disorder treated with medical cannabis, quality of life, sleep, and anxiety improved while prescribed opioid doses decreased over six months.
Quick Facts
What This Study Found
Patients showed improvements in GAD-7 anxiety scores, sleep quality, and EQ-5D-5L quality of life at 1, 3, and 6 months. Prescribed opioid doses (oral morphine equivalent) decreased. 85% were already using illicit cannabis at baseline. Only 3 patients (8.8%) reported 17 adverse events.
Key Numbers
34 patients, 79.4% male. 85.3% using illicit cannabis at baseline. 52.9% had opioid use disorder. Products: 11.8% oils, 41.2% dried flower, 47.1% combination. 8.8% reported adverse events. Improvements in GAD-7, SQS, and EQ-5D-5L.
How They Did This
Observational analysis of UK Medical Cannabis Registry data for 34 patients with substance use disorder. Outcomes measured at 1, 3, and 6 months using validated patient-reported outcome measures.
Why This Research Matters
If medical cannabis can improve outcomes for people with substance use disorder while reducing opioid requirements, it could represent a harm reduction strategy, though the observational design prevents causal conclusions.
The Bigger Picture
This study reflects a paradigm shift: treating cannabis not as a substance to abstain from but as a regulated medicine that might help people reduce more harmful substance use. The high baseline rate of illicit cannabis use suggests these patients were already self-medicating.
What This Study Doesn't Tell Us
Very small sample (34 patients). No control group or randomization. 85% already using illicit cannabis, so improvements may partly reflect switching to regulated products rather than a new therapeutic effect. Selection bias in who enrolls in a cannabis registry.
Questions This Raises
- ?Would randomized controlled trials confirm the opioid-sparing effect of medical cannabis in SUD?
- ?Does switching from illicit to regulated cannabis alone account for the observed improvements?
Trust & Context
- Key Stat:
- of patients were already using illicit cannabis at baseline, suggesting medical cannabis may formalize self-medication patterns
- Evidence Grade:
- Small observational study from a patient registry without controls. Provides signal but cannot establish causation.
- Study Age:
- 2025 publication.
- Original Title:
- UK Medical Cannabis Registry: A Clinical Analysis of Patients with Substance Use Disorder.
- Published In:
- European addiction research, 31(5), 325-335 (2025)
- Authors:
- Ghosh, Aishwarya, Erridge, Simon(22), Coomber, Ross(19), Bhoskar, Urmila, Holden, Wendy, Kamal, Fariha, Mwimba, Gracia, Sachdeva-Mohan, Simmi, Shaya, Gabriel, Usmani, Azfer, Rucker, James, Sodergren, Mikael
- Database ID:
- RTHC-06538
Evidence Hierarchy
Watches what happens naturally without intervening.
What do these levels mean? →Frequently Asked Questions
Can cannabis treat opioid addiction?
This small study found associated improvements, but cannot prove causation. The concept of cannabis as opioid substitution therapy is controversial. Most patients were already using illicit cannabis, so the study may primarily show benefits of regulated access over illicit use.
What types of cannabis products were prescribed?
Nearly half received a combination of dried flower and oils, about 41% received dried flower alone, and about 12% received oils only. This reflects real-world prescribing patterns in the UK medical cannabis system.
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Cite This Study
https://rethinkthc.com/research/RTHC-06538APA
Ghosh, Aishwarya; Erridge, Simon; Coomber, Ross; Bhoskar, Urmila; Holden, Wendy; Kamal, Fariha; Mwimba, Gracia; Sachdeva-Mohan, Simmi; Shaya, Gabriel; Usmani, Azfer; Rucker, James; Sodergren, Mikael. (2025). UK Medical Cannabis Registry: A Clinical Analysis of Patients with Substance Use Disorder.. European addiction research, 31(5), 325-335. https://doi.org/10.1159/000547696
MLA
Ghosh, Aishwarya, et al. "UK Medical Cannabis Registry: A Clinical Analysis of Patients with Substance Use Disorder.." European addiction research, 2025. https://doi.org/10.1159/000547696
RethinkTHC
RethinkTHC Research Database. "UK Medical Cannabis Registry: A Clinical Analysis of Patient..." RTHC-06538. Retrieved from https://rethinkthc.com/research/ghosh-2025-uk-medical-cannabis-registry
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.