Cannabis chronic pain study: baseline sleep and anxiety predict response

NewsUnited Kingdom

By Spliff NewsroomPublished 12 November 2026 at 20:00·3 min read

A cannabis chronic pain study based on the British Medical Cannabis Registry, published in October 2026, followed 3,744 patients in the UK for up to 24 months. Researchers found baseline sleep and anxiety predicted response better than product or dose.

The analysis draws on the UK Medical Cannabis Registry. It was led by Simon Erridge and Mikael H. Sodergren of Imperial College London, according to Hanf Magazin. It appeared in the Journal of Clinical Pharmacology.

Improvement across every measure

All measured outcomes improved significantly between baseline and 24 months: pain, sleep, anxiety and quality of life. More than half of patients reached a clinically relevant improvement on each pain measure.

Average pain severity on a 0-10 scale fell from 5.86 to 4.55. Effect sizes were d = 0.57 for pain severity, d = 0.59 for pain-related disability and d = 0.76 for quality of life.

Five distinct patient trajectories identified

A clustering analysis found five types of trajectory. All of them ended below their starting levels, the report says.

Roughly 75% of participants had used cannabis before. That detail matters when reading the results.

Baseline state outweighs product choice

Response was more closely tied to baseline sleep quality, baseline anxiety and the specific pain indication than to product or dose characteristics. Hanf Magazin summarises the finding this way: the starting condition of the patient matters more than product selection.

The study summary also suggests that the hunt for the perfect product or THC content explains less than many practitioners assume.

Side effects and limits

Adverse effects were reported by 538 patients, or 14.37%, mostly mild to moderate. Two caveats remain:

• There was no control group, so the share of improvement due to cannabis itself is unclear.
• Not all 3,744 patients gave data at 24 months, and those who dropped out often responded less well.

Wider medical context in Europe

Chronic pain is the most common indication for medical cannabis in Germany. Exilby, a cannabis-based medicine approved for chronic back pain, has been available there this year, per the same source.

Similar registries exist elsewhere, including a Minnesota registry on cannabis for autism. Randomised controlled trials remain rare, with the Charité pilot study on endometriosis pain a notable exception. The same group previously published a two-year analysis on endometriosis using the same database.

Ce que ça change pour toi

This is a registry analysis of medical patients in the UK, so it would not directly change anything for shoppers. It does not show that any product treats pain, and it should not replace medical advice.

If you follow the science, the study suggests context such as sleep and anxiety may matter as much as the product. For background on the UK, see our report on near-daily use in Great Britain. You can also browse the CBD flower collection.