“UK cannabis clinics operate as drug dealers for the middle class.” That’s the view of Robin Murray, Professor of Psychiatric Research at King’s College London, in his response to a recent study of medical cannabis and mental health conditions.
The paper Professor Murray is talking about, snappily entitled The efficacy and safety of cannabinoids for the treatment of mental disorders and substance use disorders: a systematic review and meta-analysis, spread across media outlets worldwide. At home, The Guardian, ITV and others pounced on the findings, declaring that “Cannabis is not an effective treatment for common mental health conditions” and “Medical cannabis does ‘more harm than good’”.
But ask any patient who uses cannabis for their mental health, and their lived experience tells a different story. Estimates suggest 40-50% of all patients are prescribed for psychiatric conditions, and surveys say their treatment helps them live better lives. Are all of these people wrong about their own recovery?
Behind the headlines
Skim across the coverage, and the findings appear damning: Medical cannabis simply doesn’t work when it comes to mental health. But dig a little deeper, and the results aren’t quite as simplistic. The headlines buried the positives; no increase in serious side effects, efficacy for reducing tics in Tourette’s, emerging evidence for autism/sleep, and, surprisingly, that medical cannabis can be an effective treatment for cannabis use disorder.
The Lancet paper was a systematic review and meta-analysis. Essentially, a study of studies. To come to their conclusions, researchers pooled data from randomised controlled trials (RCTs) looking at cannabinoids for mental health and substance use disorders.
The report didn’t find proof that cannabis was ineffective; the data simply wasn’t strong enough to say cannabis definitively works
The review included 22 trials covering conditions like generalised anxiety disorder, social anxiety, PTSD, ADHD, Tourette syndrome, and substance use disorders. Across these trials, the researchers found what they described as “low-certainty evidence” for efficacy.
It’s here the problem lies. The report didn’t find proof that cannabis was ineffective; the data simply wasn’t strong enough to say cannabis definitively works.
While the media took liberties with the findings, they overlooked deeper flaws. The conditions dominating headlines received different levels of scrutiny. For generalised anxiety disorder, the review found six trials. For social anxiety, three. For PTSD, one small trial from decades ago.
For depression? Zero. Not one single RCT made it into the analysis.
This isn’t because the researchers overlooked something or chose to leave it out. RCTs studying medical cannabis as a treatment for depression don’t exist. Yet multiple headlines declared, without caveat, that cannabis doesn’t work for common mental health conditions. Depression is the most common mental health condition in the UK, affecting roughly one in six adults, but there aren’t any RCT-based studies to understand how cannabis does or doesn’t help. The headlines presented evidence that doesn’t exist.
Madness in the methodology
Carl Sagan once said that “absence of evidence” and “evidence of absence” are fundamentally different things. One means we haven’t looked properly, while the other means we looked and found nothing.
The Lancet documented the former; the headlines proclaimed the latter. And the problem doesn’t just stop with what was or wasn’t studied. Various experts have raised concerns about how the research team came to their findings.
The review pooled together studies spanning decades. Trials from the 1980s combined with research from 2024. During this four-decade span, the way we diagnose mental health has changed multiple times. A diagnosis then isn’t necessarily the same as it is today.
Saxon Coop, Founder & CEO of Toke, pointed to broader issues with the evidence base: “Several studies include populations with higher rates of substance use or predisposition to other illicit drugs, which makes it harder to attribute outcomes to cannabis alone without clearer controls.
“The study also acknowledges that a large proportion of the underlying trials carry a high risk of bias or methodological limitations. When nearly half of the evidence is considered high risk, and only a small proportion is low risk, it reinforces that this is still an emerging field where stronger, more targeted research is needed.”
The trials studied widely different cannabinoid formulations. Some used CBD only, others THC dominant, and some were balanced. Delivery methods were equally varied. Oils, capsules and vaporised flower all featured. Dosing schedules, treatment durations and more were all bundled up into the same review.
Imagine a meta-analysis of “antibiotics for infection” in which researchers pooled penicillin, tetracycline, and fluoroquinolones, all administered at various doses for anywhere from three days to three months, treating everything from UTIs to sepsis.
If researchers concluded that “antibiotics show low-certainty evidence for treating infection,” it would be rightly questioned.
“Treating medicinal cannabis as one therapy is a methodological error,” said Dr Navin Naidoo, Emergency Medicine Consultant and GP. “CBD-dominant medicines, THC-dominant products and balanced formulations have very different pharmacology.”
The price of gold
RCTs are considered the gold standard of medical evidence. They use controlled environments, random participant assignment, and placebo comparisons. For cannabis, they’re nearly impossible to conduct properly. Cannabis is hard to administer ‘blind’, it has a distinct effect, smell and taste. It is made up not of one active compound, but hundreds. Each human responds uniquely to cannabis. Simply put, RCTs don’t suit cannabis, so fewer exist.
In 2022, researchers from Drug Science highlighted that real-world evidence (RWE) – data collected from patients in actual clinical practice rather than controlled trial conditions – can safely and reliably validate the efficacy of medical cannabis. “RWE has a broad range of advantages. These include the study of larger groups of patients, the use of a broader range and ratio of components of [medical cannabis], and the inclusion of more and rarer medical conditions. Importantly, and in contrast to RCTs, patients with significant comorbidities–and from a wider demographic profile–can also be studied.”
There is an abundance of RWE that shows medical cannabis works. A 2023 study followed over 3,000 patients using medical cannabis across multiple conditions. The researchers found significant improvements in pain, sleep quality, and anxiety symptoms. Patients also reported reductions in the use of opioids, benzodiazepines, and other prescription medications.
A 2022 study involving patients in the UK found that medical cannabis treatment was associated with reductions in depression severity at one, three, and six months. A recent survey of medical cannabis patients prescribed for mental health conditions found that 97% reported improvements in their well-being.
Compare the two methods, RCTs vs RWE, and you get two different outcomes. But only one method is considered to be worthy.
The traditional evidence hierarchy places RCTs at the top, but as the Drug Science study highlights, Sir Michael Rawlins, the former head of the MHRA and NICE, said in 2008 that RCTs are not the only way to validate that a treatment works.
“Randomised controlled trials, long regarded as the ‘gold standard’ of evidence, have been put on an undeserved pedestal. Their appearance at the top of hierarchies of evidence is inappropriate… They should be replaced by a diversity of approaches that involve analysing the totality of the evidence base”.
A lack of strong, high-quality evidence isn’t the same as evidence that a treatment is ineffective or harmful
RCTs were designed for conventional pharmaceuticals with patent protection, industry funding, and regulatory pathways that incentivise expensive trials.
Medical cannabis doesn’t fit that model. It’s a regulated drug in many countries, creating barriers to research. It can’t be patented in its plant form, removing the commercial incentive for pharmaceutical companies to fund trials. The stigma around cannabis makes institutional funding difficult to secure.
The problem isn’t whether cannabis works. It’s a treatment that thousands of patients report as beneficial. It remains trapped in a limbo, too hard or expensive to prove with RCTs, yet dismissed because RWE isn’t good enough.
The missing evidence: Patient voices
Once again, the most important evidence, patient voices, was missing from the media narrative. Across social media, real people described what a meta-analysis fails to grasp.
One patient, who spent five years on fluoxetine and quetiapine for depression, said that traditional pharmaceuticals “didn’t resolve the issue but just masked emotions and made me feel numb. Medical cannabis allowed me to break through the depression by analysing and rewiring my perspective. I am now so much more content with life.”
Another describes cannabis not as a cure, but as functional support: “It doesn’t magically cure my anxiety or depression, but it genuinely helps me get through tougher days and stay more level. It’s more like support than a fix.”
For someone managing multiple conditions – anxiety, PTSD, insomnia, autism – the impact is more dramatic: “It’s been transformative. The difference is night and day. I feel like myself again, my head is quieter, I can function again.”
These testimonials aren’t isolated. Countless RWE studies and patient-reported outcome reviews show cannabis can work, especially where other treatments have failed. Sadly, deep-rooted bias exists within the medical community, leaving harm and fear in its wake. Simply because the evidence provided doesn’t fit neatly into the right kind of trial.
Should patients be worried?
Those who need cannabis the most are hit hardest by these headlines. Patients can be forgiven for feeling anxious when the treatment easing their symptoms comes under attack.
As always, the truth lies beyond the clickbait. Underneath, the Lancet review uncovers a funding gap, widened not by a lack of clinical evidence, but because pharmaceutical companies can’t recoup the costs to conduct robust, randomised controlled trials.
“Patients shouldn’t feel alarmed by headlines suggesting that medical cannabis ‘does more harm than good’ for mental health,” Mike Morgan-Giles, CEO, The Cannabis Industry Council, said to leafie. “This latest review highlights what clinicians and researchers have long known: the evidence base is still developing and in areas remains limited and inconsistent.”
The AMA, an organisation deeply against the rise of cannabis medicine in Australia, conducted the Lancet report. Yet in their own conclusion, the authors admit “there is a crucial need for RCTs with larger and more representative samples”.
No medicine is perfect. Antidepressants may work for many, but the side effects can be brutal. Opioids can cut through pain, but can cause catastrophic harm. Only cannabis, through decades of stigma and misconception, faces such intense scrutiny from the press.
It’s unlikely there will be any immediate impact from these headlines here in the UK. For patients currently prescribed cannabis, or anyone considering medical cannabis treatment, the most important thing is to keep in regular contact with their clinic, which can assess and record their individual circumstances, monitor outcomes, and adjust treatment as needed. The more patient data available, the more understanding we have.
“A lack of strong, high-quality evidence isn’t the same as evidence that a treatment is ineffective or harmful. Many patients report meaningful improvements in symptoms such as anxiety, sleep, and overall quality of life under medical supervision,“ Morgan-Giles added.
“This review should be seen as a call for more rigorous research instead of a reason for patients to be concerned or discontinue treatment that is working for them safely and effectively.”
Professor Murray’s claim that cannabis clinics only exist as drug dealers to the middle class is reckless. His comments sow seeds of anxiety amongst people who live with genuine mental health concerns – a cruel irony. The reality is that cannabis is proving to be an effective medicine for tens of thousands in the UK across class, gender, race and age. They know what works for them, and the industry doesn’t think another round of sensationalism is a cause for worry.
Perhaps, in time, the media might catch up to the reality of being a cannabis patient in the UK.
