UK Medical Cannabis Registry Shows Improved Health in First 678 Patients | Research

The takeaway

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.

UK clinicians considering medical cannabis prescribing; health policy researchers; patients seeking legal medical cannabis in the UK.

Self-reported health improvement: Cohen's d = 0.77 at 3 months

What the researchers 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).

Why it 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 numbers in context

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 the study worked

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.

What this study cannot 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.

How to read the evidence

Moderate: prospective registry with validated outcome measures, but limited by small follow-up sample and no control group.

When this study was published

Published in 2022, registry launched August 2020.

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.

Questions still open

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?

Common 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 the original research

Developing a real-world evidence base for prescribed cannabis in the United Kingdom: preliminary findings from Project Twenty21.

Psychopharmacology, 239(5), 1147-1155

View on PubMed ↗Publisher’s paper ↗

Citation

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