Medical cannabis for anxiety and mental health: is the evidence being misinterpreted?

While the review itself raises important questions about the quality of existing randomised-controlled trial (RCT) data, the way the findings have been presented oversimplifies a far more complex and evolving evidence base that, in many ways, does actually support medical cannabis treatment in the UK. 

It represents a narrow slice of the available evidence, rather than a definitive assessment of clinical outcomes, including real world patient data, registry studies, and prospective cohort research. 

Is the Lancet Psychiatry review being misinterpreted?

Not necessarily. The findings of the report are clear. 

The issue is how the media are positioning the findings from this single piece of analysis, and how it is being treated as the ‘be-all-and-end-all’ of the entire evidence base.

That is simply not the case. 

The review does report no significant effects for anxiety or PTSD within available RCT data, and no RCT evidence for medical cannabis for depression at all. These findings are important, but they are heavily limited to one single form of scientific evidence. The absence of RCT evidence for depression within this review does not mean that no evidence exists. It reflects a lack of eligible controlled trials within the study’s inclusion criteria, rather than a complete absence of clinical data.

And while randomised controlled trials are considered the gold standard in medical research, they are certainly not the only way to evaluate treatment outcomes, particularly in areas like medical cannabis where research is evolving. 

What the Lancet Psychiatry review actually looked at, and why that matters for how the results are interpreted

The review analysed 54 randomised controlled studies that spanned a 45-year period. On the surface, that does appear to represent a substantial evidence base. But in practice, it is a little less cohesive than that number suggests.

The studies that were included in the review vary significantly in design. This includes major differences in the: 

• Cannabinoid composition, including THC-dominant, CBD-dominant, and combination treatments

• Dosing strategies, including size, frequency, and titration approaches 

• How the treatments were administered, with most of the trials focused on medical cannabis oil being taken orally

• Treatment duration, ranging from quite short term to months (or even years) long studies

• Study participant populations, including differences in diagnosis, severity, and comorbidities

The variation across these studies has direct implications for how the results should be understood, and presented to the public.

Some trials focused on isolated cannabinoids, others had a mix of cannabinoids and terpenes. But only a far smaller number included whole-plant-derived products, which is more representative of what the overwhelming majority of UK medical cannabis patients are prescribed in 2026. 

This level of variation makes it more difficult to identify clear and consistent effects when results are combined in a review.

In short: Limited RCT evidence does not equate to absence of real world clinical effect, and the variation across the included studies, coupled with the relative absence of the more commonly prescribed formats such as vaporised medical cannabis flower inevitably limits the strengths of the conclusions that can be drawn.

What are UK patients actually experiencing with medical cannabis for mental health?

The interpretation presented in recent media does not align with what patients have reported during real-world clinical treatment.

In November 2025, Releaf, recognised as the most trusted medical cannabis clinic in the UK (with more than 5000 trust pilot reviews and an average score of 4.7 out of 5) commissioned the largest ever survey of UK active medical cannabis patients.

Of the 1,669 respondents, over one third (672 respondents) reported that they were prescribed legal medical cannabis for anxiety, depression, PTSD, or a combination of the three mental health conditions.

The patients who chose to take part in this survey received no financial incentive or compensation of any kind to take part in this survey. Participation was completely voluntary, and their responses were collected separately from any clinical consultation.

The findings from Releaf’s largest survey of UK medical cannabis patients

Across the 672 patients reporting use of medical cannabis for anxiety (n=524), depression (n=303), and PTSD (n=84), outcomes are both consistent and clinically meaningful. Keep in mind that there was overlap between groups, which is expected in real-world datasets, and why the numbers presented do add up to more than 672. 

Let’s break down the findings into a few key areas.

Treatment effectiveness

The effectiveness of the legally prescribed Releaf medical cannabis treatment options shows a very consistent signal across all three conditions. 

• 94% report at least moderate effectiveness

• 80% report treatment as very (41%) or extremely effective (39%) 

• Fewer than 4% report limited or no effect

• PTSD shows the strongest overall response, followed closely by anxiety and depression

Quality of life

While quality of life is a somewhat subjective data point, it did show the most uniform and highest level of improvement across the survey results.

• 98% report improved quality of life

• 67% report significant improvement, with another 31% reporting some improvement 

• Around 2% report no change or a decline

Daily functioning

Daily functioning refers to a patient’s ability to manage routine activities such as sleep, self-care, concentration, emotional regulation, and general day-to-day responsibilities. 

• Improvements in daily functioning closely mirror the positive results reported for both treatment effectiveness and quality of life, almost 87% of respondents reporting improved day-to-day functioning

Work and study impact

The impact that medical cannabis treatment has on the work and study capabilities of respondents represents a more complex layer of recovery. For some patients, it may take months, even years of effective treatment before they are ready to return to work, increase their workload, or re-engage with education. That said:

• Just under 70% reported improved ability to work or study

• Around 25% report no change

• Around 3% reported a decline

• Around 3% were unsure

Full cohort breakdown

The full breakdown of outcomes across all anxiety, depression, and PTSD respondents is shown below.

What do other recent studies on medical cannabis for mental health show beyond the Lancet review?

Real-world studies show sustained improvements over time for depression

One of the more interesting studies of the past few years was published in the Journal of Affective Disorders in 2026. Titled “UK Medical Cannabis Registry: A two-year case series of clinical outcomes in depression”, the study tracked outcomes in 698 patients diagnosed with depression over a 24-month period. Similar to the Releaf patient survey, this study reflects how medical cannabis is prescribed and administered in routine clinical care.

While the study does not present specific percentage-based outcomes in the same way as survey data, it instead uses validated clinical scoring systems to track changes in symptom severity over time.

Key findings include:

• Significant reductions in depression severity scores at 1, 3, 6, 12, and 24 months

• Parallel improvements in anxiety scores over the same time periods

• Sleep quality scores improved early and remained stable long term

• Quality of life scores increased consistently across all follow-ups

• The majority of clinical improvement occurred within the first 12 weeks

H3: Prospective cohort study shows anxiety and depression symptom reduction within months of starting medical cannabis treatment

“Acute and chronic effects of medicinal cannabis use on anxiety and depression in a prospective cohort of patients new to cannabis”, published on 1 December 2025 focused on patients just beginning their medical cannabis treatment for anxiety and depression. It showed, very clearly, how symptoms changed in the early stages of treatment for the study participants. 

Key findings include:

• Significant reductions in both anxiety and depression scores at 1, 3, and 6 months

• The proportion of patients above clinical thresholds fell from 81% (anxiety) and 76% (depression) at baseline to below 50% within 3 months

• Acute symptom reductions were also observed following individual doses

• Effects showed a dose-response pattern, with moderate doses producing the strongest improvements

Medical cannabis for PTSD study presents some of the strongest real-world outcomes

“Medicinal cannabis for treating post-traumatic stress disorder and comorbid depression: real-world evidence”, published by Cambridge University Press on 12 March 2024 reported some very compelling results. 

Medical cannabis for PTSD was associated with statistically significant reductions in symptom severity within the first three months of treatment, with continued improvements observed over time.

Key findings include:

• Mean PTSD scores reduced from 58.0 at baseline to 47.0 at 3 months

• Patients with comorbid depression showed larger improvements (mean reduction of 15.3 vs 7.0)

• Improvements were also observed in anxiety symptoms, sleep quality, and general health

• Quality of life scores increased alongside symptom reduction

• Benefits were sustained in longer-term follow-up data (up to 18 months in related cohorts)

These findings are particularly relevant because PTSD is closely linked to sleep disruption and hyperarousal, both of which showed meaningful improvement in this cohort.

And the findings from these real-world studies line up with the results from Releaf’s largest ever survey of active medical cannabis patients in the UK. 

Is medical cannabis for anxiety, depression and PTSD effective?

The current narrative being pushed by mainstream media outlets isn’t necessarily out of line with the research they have decided to highlight, but that’s the issue. It is a simplified conclusion that simply does not fully or accurately reflect the complexity of the bank of emerging evidence. 

The Lancet review raises valid questions about the strength of RCT data. But when viewed alongside real-world clinical outcomes, registry studies, and prospective research, a more nuanced picture emerges.

That picture is this: Medical cannabis is far from a settled science, but if you listen to the patients actually prescribed these legal treatment options over the past seven years here in the UK, and look at how they are performing in real life clinical settings, the findings are very positive. 

Not for every single patient. Not in every case. And what works for one patient may not be effective for the next. 

But there is more than enough emerging data to warrant serious attention rather than a continuation of the type of dismissal, stigma, and demonisation that has plagued medical cannabis in this country (and abroad) for more than a century.

If you would like to learn more about your potential eligibility for a medical cannabis prescription here in the UK, head to our fast and free medical cannabis eligibility checker. It takes less than 20 seconds to complete, and will offer you a clear answer whether medical cannabis may be a legal treatment route for your health needs.

For further information, expert comment, or media enquiries on this topic, please contact our Chief Medical Officer, Graham Woodward, at press@releaf.co.uk.