Two Years of Medical Cannabis for Depression: UK Registry Shows Sustained Improvement | Research

The takeaway

UK medical cannabis patients with depression showed significant improvements in depression, anxiety, sleep, and quality of life sustained over 24 months, with mostly mild side effects.

Psychiatrists, medical cannabis prescribers, depression researchers, health policy makers

What the researchers found

Among 698 patients treated with cannabis-based medicinal products for depression, statistically and clinically significant improvements were observed across PHQ-9 (depression), GAD-7 (anxiety), sleep quality, and EQ-5D-5L (quality of life) at all time points up to 24 months. Improvements were most prominent in the first 3 months. Only 9% reported adverse events, 87% of which were mild or moderate.

Why it matters

Depression is among the most common conditions for which people seek medical cannabis, but clinical evidence has been scarce. This is one of the largest and longest real-world datasets showing sustained benefits across multiple outcomes.

The numbers in context

698 patients analyzed from 34,563 in registry (2.02%). At baseline, 50.86% had severe anxiety (GAD-7 ≥15). Depression-anxiety correlation: r=0.67. 9.03% reported at least one adverse event; 87.26% were mild/moderate. Improvements significant at all timepoints (p<0.001).

How the study worked

Longitudinal analysis of 698 patients from the UK Medical Cannabis Registry (34,563 total patients), with patient-reported outcome measures collected at baseline and 1, 3, 6, 12, 18, and 24 months. Validated instruments included PHQ-9, GAD-7, SQS, EQ-5D-5L, and PGIC.

What this study cannot tell us

Observational registry data — no control group or randomization. Selection bias (patients who improve may be more likely to stay in treatment). Cannot establish causal relationship. Only 2.02% of registry patients had depression as primary condition.

How to read the evidence

Large registry with validated measures and long follow-up, but observational design without control group prevents causal conclusions.

When this study was published

Published 2026 using UK Medical Cannabis Registry data through January 2025.

The bigger picture

The UK Medical Cannabis Registry is generating the kind of real-world evidence that clinical trials haven't yet provided. While observational data can't prove causation, 24 months of consistent improvement across multiple measures is a meaningful signal.

Questions still open

Would these improvements hold up in a randomized controlled trial? What cannabis formulations and doses were most effective? Are the improvements driven by cannabis itself or by engagement with a medical care pathway?

Common questions

Does medical cannabis help with depression?

In the UK's largest medical cannabis registry, 698 patients treated for depression showed significant improvements in depression scores, anxiety, sleep, and quality of life sustained over two years — though without a control group, we can't be certain cannabis caused the improvements.

Is medical cannabis for depression safe?

In this study, 91% of patients reported no adverse events over 24 months. Among the 9% who did, 87% of events were mild or moderate. However, this represents patients under medical supervision, not self-medication.

Read the original research

UK Medical Cannabis Registry: A two-year case series of clinical outcomes in depression.

Journal of affective disorders, 399, 121130

View on PubMed ↗Publisher’s paper ↗

Citation

Lillywhite, Elizabeth; Erridge, Simon; Clarke, Evonne; McLachlan, Katy; Coomber, Ross; Asghar, Muhammed; Bhoskar, Urmila; Crews, Matthieu; De Angelis, Andrea; Imran, Muhammad; Kamal, Fariha; Korb, Laura; Mwimba, Gracia; Sachdeva-Mohan, Simmi; Shaya, Gabriel; Rucker, James J; Sodergren, Mikael H. (2026). UK Medical Cannabis Registry: A two-year case series of clinical outcomes in depression.. Journal of affective disorders, 399, 121130. https://doi.org/10.1016/j.jad.2025.121130