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Medical Cannabis improves Quality of Life by over 50% - Preliminary Results from Project Twenty21

Doctor prescribing Medical Cannabis


C. Sakal, M. Lynskey, A. K. Schlag, D. J. Nutt


May 11, 2021

We’re delighted to announce the first findings from Project Twenty21, the UK’s largest-ever medical cannabis patient study. 

Over 900 patients have now received licensed prescriptions for medical cannabis and agreed for Drug Science to collect and analyse their medical data under Project Twenty21.

Using the EQ-5D-5L* rating of quality of life, our data shows that these patients are in substantially poorer health than the general population, and have been unable to manage their diagnosed conditions with commonly prescribed medications. 

Our findings show that legally prescribed cannabis provides clinically significant improvements in the quality of life of patients living with conditions such as Chronic Pain, Multiple Sclerosis, Tourette’s Syndrome, Epilepsy, and Post Traumatic Stress Disorder (PTSD).

The publication follows our recent paper which found that medical cannabis improves quality of life more than any other treatment for chronic neuropathic pain, and also an April 2021 statement from the National Institute for Clinical Excellence (NICE). The statement recommended a move away from relying too heavily on opioids for treating pain, towards a more holistic approach:

"there is little or no evidence that [commonly prescribed drugs, such as benzodiazepines or opioids] make any difference to people’s quality of life, pain or psychological distress, but they can cause harm, including possible addiction"

– National Institute of Clinical Excellence (NICE)

What did the research find?

As such, today’s report is the first published real-world data to be collected on medical cannabis in the United Kingdom. Patients’ experiences and the EQ-5D-5L data show:

  1. A 51% increase in patients’ self-reported health and ability to lead a more normal life, demonstrated by an average increase from 40.7 to 61.5 after 3 months.

  2. Significant improvements in patients’ ability to manage debilitating secondary conditions such as anxiety, insomnia and depression.

  3. Patients are now able to avoid criminality with legal prescriptions. 63% had previously felt compelled to turn to illegal use in an attempt to manage their conditions.

  4. Medical Cannabis prescriptions provide a welcome alternative to commonly prescribed medicines that have a high risk of dependency and serious side effects, including dependency.

A lack of clinical evidence has made it difficult for doctors to confidently prescribe legal medical cannabis in the UK. These new findings provide a major step forward, and help to clarify the benefit these medicines can have for thousands of seriously ill patients.

– Prof David Nutt, Founder of Drug Science

Real-world data vs randomised controlled trials

Due to the challenges of studying medical cannabis through randomised controlled trials (RCTs), Project Twenty21 was set up to develop evidence using real-world data to assess the effectiveness and efficacy of medical cannabis. 

While it is true that an observational study may not be as rigorous as an RCT, it is important to understand that results from RCTs do not always translate to real-world therapeutic use.

For example, many patients being prescribed medical cannabis suffer from multiple pathologies which would exclude them from an RCT and make it difficult to predict their health outcomes from RCT results alone.

Therefore it is important that real-world data is also available to build a comprehensive evidence base for medical cannabis. 

How does Project Twenty21 work?

Project Twenty21 is an observational study which provides a framework to enable data collection but which is not directly involved with either patients or prescribing. Consultation and prescription is conducted by specialist clinicians, aligned to the study.

As we collect and analyse patient data, Project Twenty21 also aims to improve patient access to medical cannabis. Drug Science has partnered with licensed medical cannabis producers (Bod Australia, Cellen Therapeutics, Khiron Life Sciences, JMCC Group, Lyphe Group, alongside tech partner Alta Flora) to reduce the cost of medical cannabis products, increasing affordability and therefore access to medical cannabis.

These producers are not able to influence the study’s outcomes because Drug Science has ensured that they have no control over which products are included in the Project Twenty21 formulary nor which products are prescribed by its clinicians. 

In order to obtain a prescription, prospective patients contact one of the study’s approved clinics. A doctor will then confirm that the patient is eligible for the study (see below), and decide which treatment is best.

The prescribed treatment will depend on both condition and symptoms, and could result in a patient being prescribed more than one type of medical cannabis product. Once the prescription has been issued, the medical cannabis product is sent to the patient by courier from a specialist pharmacy.

Who is eligible for medical cannabis under Project Twenty21?

Every patient enrolled had at least two ‘failed treatments’ on their medical records, where commonly prescribed medications, such as opioids, had little to no effect on the ability of patients to manage their conditions. Evidence of this is a compulsory requirement for participation, and central to the study’s inclusion criteria.

Chart on the Primary Condition

How does Project Twenty21 assess health outcomes of medical cannabis treatment? 

Patient health was assessed at the initial appointment with a clinician and again at a 3-month follow-up appointment. These were conducted using the EQ-5D-5L methodology. Other measures were used to assess changes in mood/depression,By 13th March 2021, a total of 75 individuals had completed both initial and 3-month appointments. 64.0% were male, 34.7% were female and one individual identified as non-binary. The average age was 39.9 years (range = 20.2 to 75.7). The vast majority of patients (56%) reported chronic pain as their primary condition.

“Our patient population comprises a huge age range, and often have multiple health problems.Also, the low quality of life that they experience demonstrates just how unwell many of them are. Stereotypes of medicinal cannabis users as being young, healthy recreational users looking for a legal source could not be further from the truth.”

– Dr Anne Schlag, Head of Research at Drug Science


Despite the limitations of real-world data, when combined, various global databases, including T21, show an emerging pattern of evidence which ought to be taken into account when regulating the prescription of CBMPs. With many clinicians demanding better and faster evidence to inform their decisions around prescribing CBPMs, findings from real-world data may offer potential solutions to the lack of randomised clinical trials.

Future T21 research will focus on examining the effectiveness of cannabis-based medical products in reducing symptomatology across different primary conditions and on improving quality of life. We will also examine the extent to which use of these products may alter use of other prescribed pharmaceuticals such as opioids.

Capitalising on the strengths of real-world data (e.g. large sample size and heterogenous patient characteristics), we will also examine whether the longitudinal trajectories of symptomatology and quality of life may vary between patient groups (e.g. those with specific patterns of comorbidity or co-occurring treatment).

Finally, the availability of longitudinal data on patterns of use will allow an examination of the potential development of tolerance while we will also collect information on any side effects or adverse reactions.

Together, this information will provide a solid foundation to assess the safety and effectiveness of prescribed cannabis in the ‘real world’ and the extent to which safety and effectiveness may vary between product types or patient characteristics.

For open-access to the full report of this research, see below:

*The EQ-5D-5L rating is an established standard to quantify the wellbeing of patients with cancer, cardiovascular disease, dementia and numerous other clinical conditions.

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