Patients in the UK have had legal access to medical cannabis since November 2018. Indeed, medical cannabis is now permitted in over 50 countries around the world for a wide range of conditions.
New research published in The Journal of Clinical Pharmacology has looked at what happens to patients who are prescribed medical cannabis in the UK. The study followed nearly 9,000 patients over two years. It is one of the largest studies of its kind.
This article explains what the researchers found. We also explain what the study can and cannot tell us.
What did the study look at?
While randomised controlled trials remain important, the complexity of the cannabis plant and its extracts often presents challenges in conducting these trials. In this context, the analysis of real-world evidence is important in understanding the outcomes of patients to guide current clinical practice and future research.
To this end, in 2019, Curaleaf Clinic established the UK Medical Cannabis Registry. The UK Medical Cannabis Registry collects information from patients who are prescribed medical cannabis. The researchers wanted to know how patients’ quality of life changed over time.
Quality of life means how well someone feels day to day. It includes things like being able to do normal activities, levels of pain, anxiety, and sleep quality.
The study included 8,945 patients. Researchers asked them to fill in questionnaires at the start, then at 1, 3, 6, 12, 18 and 24 months.
Who were the patients in the study?
The average age was 42 years old. About 60% were male and 40% were female.
The most common reasons for treatment were chronic pain (about half of all patients), anxiety disorders or post-traumatic stress disorder (about 1 in 5), and depression (about 1 in 13).
Most patients had already tried other treatments before being prescribed medical cannabis. Many had used cannabis before, either legally in other settings or illegally.
What did patients report about their quality of life?
The researchers used a standard questionnaire called the EQ-5D-5L. This measures five areas: mobility, self-care, usual activities, pain or discomfort, and anxiety or depression.
Over 70% of patients reported changes in their overall quality of life scores at each check-in point. The average scores changed from baseline and stayed improved throughout the two years.
For anxiety, just over half of patients (54%) reported a meaningful improvement by 24 months. For sleep quality, 44% reported a meaningful improvement.
Among patients who were taking opioid painkillers when they started, about 1 in 5 (23%) reported a meaningful reduction in their opioid use.
Did patients respond differently to treatment?
Yes. The researchers utilised a machine learning approach to identify 10 different patterns of response. Eight of these patterns showed improvement in quality of life. These eight groups made up about 78% of all patients.
Some patients improved quickly in the first month. Others improved more slowly over many months. One group stayed about the same. One small group reported getting worse.
The researchers found that a patient’s starting characteristics were better at predicting outcomes than the specific products they were prescribed. This suggests that who the patient is matters more than which exact product they receive.
What about side effects?
About 14% of patients reported side effects. The most common were fatigue, dry mouth, headache, and feeling sleepy.
Most side effects were rated as mild (42%) or moderate (43%). Serious side effects were uncommon. Patients who had used cannabis before were less likely to report side effects than those who were new to it.
What are the limits of this study?
This is important to understand. This was an observational study, not a clinical trial. This means the researchers watched what happened to patients. They did not compare them to a group who received no treatment or a placebo treatment.
Because of this, we cannot say that the changes were definitely caused by the treatment. Some changes might have happened anyway. Some might be due to the placebo effect. This is when people feel better because they expect to feel better.
The patients in this study paid for their own treatment. This may mean they were more motivated or had different characteristics than the general population. Not all patients completed all the questionnaires over two years.
The researchers note that more high-quality clinical trials are needed to fully understand how well medical cannabis works and for whom.
What does this mean for patients?
This study adds to the real-world evidence on medical cannabis in the UK. It suggests that many patients who are prescribed medical cannabis report changes in their quality of life over time.
However, not everyone responds the same way. Some patients reported no change or got worse. The research cannot tell us in advance who will benefit.
Medical cannabis is typically considered after other treatments have not worked well enough. A specialist doctor needs to assess whether it might be suitable for each individual patient.
Wondering if you might be eligible?
If you live with a chronic condition and have not found relief from other treatments, you may wish to explore whether medical cannabis could be an option for you.
Curaleaf Clinic offers eligibility assessments to help you understand whether you might be suitable for a consultation. This assessment looks at your medical history and current treatments.
