In a new multi-clinic survey, the majority of UK patients being treated with medical cannabis for anxiety, depression, and PTSD report improvements in their symptoms.
The survey gathered responses from 6,282 patients across the clinics Mamedica, Alternaleaf, CB1 Medical, and Curaleaf, including a 5,128-patient sub-cohort of those who were prescribed the treatment for anxiety, depression, or post-traumatic stress disorder (PTSD).
Among this group, 97.6% reported improvement in symptoms, with 92.3% reporting improvement in sleep, and 93.5% reporting improvement in their ability to function day-to-day.
A further 90.7% said medical cannabis was more effective than previous treatments tried, while 88.3% said it was the most effective treatment they had tried for their condition.
The findings come against a backdrop of sustained pressure on UK mental health services, with more than four million people in contact with NHS mental health, learning disability and autism services in 2024/25.
Published estimates from the STAR*D trial and subsequent analyses suggest that around 30% of patients with major depression do not achieve adequate symptom relief after multiple treatment attempts.
Commenting on the survey results, Dr Imogen Kretzschmar, a Consultant Psychiatrist, said: “These findings reflect patterns we see in clinical practice, particularly in patients with long-standing or treatment-resistant conditions. Improvements in sleep, anxiety and functional capacity are clinically interdependent, and when they occur together, they represent meaningful change for patients. At the same time, these treatments require careful patient selection, risk assessment and ongoing monitoring, and are not appropriate for all individuals.”
Growing body of real-world evidence
The clinics have stressed that these cross-sectional, voluntary patient survey findings should not be interpreted as definitive evidence of efficacy for anxiety, depression, or PTSD more broadly. However, they say it adds to a growing body of real-world evidence, including that collected through the UK Medical Cannabis Registry, Project Twenty21, and international datasets, supporting considered prescribing in patients who have not benefited from first-line treatments.
In the UK, medical cannabis can only be prescribed by doctors listed on the GMC Specialist Register and is considered where conventional treatments have not been effective or appropriate. Prescribing decisions are made through multidisciplinary team review, with ongoing monitoring and follow-up. Clinics are regulated by the Care Quality Commission and operate within a strictly controlled clinical framework.
This is the first time multiple UK medical cannabis clinics have pooled patient experience data at this scale, with intentions to repeat the survey annually to build a recurring benchmark for patient-reported outcomes across the sector.
Against this backdrop, medical cannabis was widely reported as well tolerated, with a significant proportion of patients reducing or stopping other medications following treatment.
Jon Robson, CEO of Mamedica, described the results as ‘resounding’ and said they speak to a ‘clear trend of efficacy across the industry that needs to be acknowledged beyond the realms of patient and clinician circles’.
Nabila Chaudri, Medical Director and Pharmacist at Alternaleaf Clinic, added: “When a large proportion of patients report that medical cannabis has been more effective for them than previous treatments they have tried, it highlights the potential impact this approach may have on people’s day to day lives. These findings are particularly noteworthy given that treatment is delivered within a clinician-led, carefully regulated framework, with a strong focus on patient safety, clinical oversight and outcomes.”
Calls for government support
The consortium is now calling for increased government and research council funding for randomised controlled trials examining cannabis-based medicinal products in treatment-resistant anxiety, depression and PTSD.
Prof Mike Barnes, Chair of The Medical Cannabis Clinicians Society (MCCS), commented: “These findings reflect what clinicians see in practice: that for carefully selected patients with genuine unmet need, medical cannabis can form a meaningful part of a broader treatment plan. Data at this scale, showing improvement across symptoms, sleep and daily functioning, do not prove causation, but they are too substantial to set aside. We need better trials, and we support government funding for rigorous independent research. In the meantime, this kind of multi-clinic collaboration on patient experience is exactly the transparency the sector needs.”
They are also urging continued recognition of the role played by the UK Medical Cannabis Registry and other real-world data sources in supporting pharmacovigilance and long-term outcomes research, alongside a more transparent, sector-wide approach to publishing patient outcomes. The survey is intended as an initial step towards broader data sharing and clinical scrutiny.
Dr Simon Erridge, Director of Research at Curaleaf Clinic, added: “The outcomes of this survey build on data published by the UK Medical Cannabis Registry, alongside real-world evidence from regions where medical cannabis prescribing for mental health has been established for longer than in the UK. The findings support calls for further randomised controlled trials to determine whether medical cannabis could be considered earlier in the treatment pathway for these patients and/or within the NHS.”
