A two-year study of 3,744 patients with chronic pain found significant improvements in pain, sleep quality, anxiety and overall quality of life among those using medical cannabis. More than half of the patients with pain assessments recorded at 24 months achieved a clinically meaningful reduction in pain, although the study’s observational design means the findings show an association rather than proving causation.
Numerous studies have already examined the effects of cannabis on conditions such as chronic pain, anxiety and sleep disorders. But this is a double-edged sword: while research into the plant’s properties is certainly welcome, studies have also produced conflicting findings, sometimes due to differences in research quality or the interests that may influence them.
This is why large-scale studies conducted over extended periods are particularly relevant. Recently, a team of researchers in the United Kingdom published the results of just such a study. The study included 3,744 patients who had been prescribed medical cannabis for chronic pain. Of these, 1,309 had pain intensity assessments recorded at 24 months.
Cannabis for Pain: What the Latest Study Says
The study, published in the Journal of Clinical Pharmacology, found an association between medical cannabis treatment and statistically significant improvements in chronic pain intensity, sleep quality, anxiety symptoms and health-related quality of life. As reported by The Marijuana Herald, the patients were enrolled in the UK Medical Cannabis Registry and were assessed before treatment and at 1, 3, 6, 12, 18 and 24 months after starting treatment.
As for the sample, participants had an average age of around 46, and 58% were men. Nearly three-quarters of participants had used cannabis before, while 57% were already using it when they began treatment.
The researchers examined overall treatment outcomes and differences in individual responses. To do so, patients were required to complete standardized assessments measuring pain intensity, how pain interfered with daily activities, anxiety, sleep quality and overall health status. The study found statistically significant improvements in the assessed measures of pain, sleep, anxiety and health-related quality of life over the two-year period.
A total of 538 patients—14.37% of the sample—reported adverse effects, most of which were classified as mild or moderate.
Of the 3,744 patients included in the study, 1,309 had pain intensity assessments recorded at 24 months. In this group, mean pain scores decreased from 5.86 to 4.55 on a scale of 0 to 10. In addition, among patients with assessments recorded at 24 months, 56.7% achieved a clinically meaningful reduction in pain intensity. Based on the different treatment response patterns they identified, the researchers concluded that some patients experienced substantially greater or longer-lasting pain relief than others. While the effects of cannabis can vary depending on its form, dosage, method of administration and individual physiology, the study found that factors such as sleep quality, anxiety and the reason for treatment were more strongly associated with differences in patient responses than product characteristics or dosage. This is why medical cannabis should not be considered a one-size-fits-all solution.
The study also evaluated changes in conventional medication use: an estimated 23% of patients who were taking opioids at baseline achieved a clinically meaningful reduction in their daily dose after two years. This finding is consistent with some research suggesting that medical cannabis could help reduce opioid use, although the available evidence remains limited. It is particularly relevant in the context of the opioid crisis affecting different parts of the world.
However, because this was an observational study rather than a randomized controlled trial, the results show an association between medical cannabis treatment and the observed improvements, but do not establish that the treatment caused those improvements. This is why more controlled clinical trials are needed to assess the effects of cannabis more accurately. A less restrictive regulatory framework could facilitate further research and expand access to high-quality evidence.
