UK Medical Cannabis Registry Shows Improved Health in First 678 Patients

Project Twenty21, the UK's first medical cannabis registry, enrolled 678 patients primarily with chronic pain (56%) and anxiety (32%), with preliminary 3-month data showing a significant improvement in self-reported health.

Sakal, C et al.·Psychopharmacology·2022·Moderate EvidenceProspective Cohort
RTHC-04191Prospective CohortModerate Evidence2022RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Prospective Cohort
Evidence
Moderate Evidence
Sample
N=75

What This Study Found

678 patients enrolled in 7 months. 64% male, average age 38.7 years. Most common conditions: chronic pain (55.6%), anxiety disorders (32.0%). High multi-morbidity including insomnia and depression. Three-month follow-up of 75 patients showed significant self-reported health improvement (Cohen's d=0.77, 95% CI 0.51-1.03).

Key Numbers

678 enrolled in 7 months. 64% male. Mean age 38.7 (range 18-80). Chronic pain: 55.6%. Anxiety: 32.0%. 3-month follow-up (n=75): EQ-5D VAS improvement Cohen's d=0.77 (95% CI 0.51-1.03). High multi-morbidity rates.

How They Did This

Prospective observational registry launched August 2020. Patients prescribed legal cannabis through UK clinics enrolled and completed EQ-5D-5L health assessments at baseline and follow-up. Descriptive analysis of first 7 months of enrollment with preliminary 3-month outcome data.

Why This Research Matters

Despite legalizing medical cannabis in 2018, the UK has issued very few NHS prescriptions. Project Twenty21 is building the real-world evidence base that clinicians demand before prescribing, bridging the gap between legalization and clinical practice.

The Bigger Picture

The UK situation is unique: medical cannabis is legal but functionally inaccessible through the NHS. Project Twenty21 represents a pragmatic approach to generating the evidence needed to change clinical practice, similar to registry approaches used for other medications.

What This Study Doesn't Tell Us

Observational design without a control group. Only 75 patients had 3-month follow-up data at time of publication. Self-reported health improvements could reflect placebo effects or regression to the mean. Patients paying privately for cannabis may differ from typical NHS populations.

Questions This Raises

  • ?Will the self-reported improvements persist at longer follow-up?
  • ?Will the registry data be sufficient to persuade NHS prescribers?
  • ?How do UK outcomes compare to similar registries in other countries?

Trust & Context

Key Stat:
Self-reported health improvement: Cohen's d = 0.77 at 3 months
Evidence Grade:
Moderate: prospective registry with validated outcome measures, but limited by small follow-up sample and no control group.
Study Age:
Published in 2022, registry launched August 2020.
Original Title:
Developing a real-world evidence base for prescribed cannabis in the United Kingdom: preliminary findings from Project Twenty21.
Published In:
Psychopharmacology, 239(5), 1147-1155 (2022)
Database ID:
RTHC-04191

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Enrolls participants and follows them forward in time.

What do these levels mean? →

Frequently Asked Questions

Is medical cannabis available in the UK?

Medical cannabis was legalized in November 2018, but very few NHS prescriptions have been issued. Most patients access it through private clinics. Project Twenty21 is building the evidence base that may help expand NHS prescribing.

What conditions are treated with medical cannabis in the UK?

In this registry, the most common conditions were chronic pain (55.6%) and anxiety disorders (32.0%), with high rates of co-occurring insomnia and depression.

Read More on RethinkTHC

Cite This Study

RTHC-04191·https://rethinkthc.com/research/RTHC-04191

APA

Sakal, C; Lynskey, M; Schlag, A K; Nutt, D J. (2022). Developing a real-world evidence base for prescribed cannabis in the United Kingdom: preliminary findings from Project Twenty21.. Psychopharmacology, 239(5), 1147-1155. https://doi.org/10.1007/s00213-021-05855-2

MLA

Sakal, C, et al. "Developing a real-world evidence base for prescribed cannabis in the United Kingdom: preliminary findings from Project Twenty21.." Psychopharmacology, 2022. https://doi.org/10.1007/s00213-021-05855-2

RethinkTHC

RethinkTHC Research Database. "Developing a real-world evidence base for prescribed cannabi..." RTHC-04191. Retrieved from https://rethinkthc.com/research/sakal-2022-developing-a-realworld-evidence

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.