Private clinics handing out ultra-strong medicinal cannabis for anxiety and depression despite ‘no evidence’ it works
Experts have warned that medicinal cannabis, prescribed to thousands of Britons for anxiety and depression, may not actually work.
While NHS prescriptions remain tightly controlled, dozens of private clinics are handing out the drug after just one video consultation, promising it can be delivered directly to patients’ doors the next day.
Experts fear vulnerable patients are being given the powerful drugs for mental health problems despite little evidence they are effective – potentially delaying treatments that are more likely to help.
The warning comes from a landmark study published in The Lancet Psychiatry, which analysed 54 clinical trials spanning 45 years.
Researchers found no evidence that medicinal cannabis is effective for anxiety, depression or post-traumatic stress disorder.
While the review found it may have benefits for some conditions – including epilepsy, chronic pain, autism, insomnia, and Tourette’s syndrome – the overall quality of evidence was low, and the authors said was rarely justified.
Lead author Dr Jack Wilson, from the University of Sydney’s Matilda Centre, said cannabis medicines could do more harm than good, including increasing the risk of psychotic symptoms, cannabis dependence, and delaying patients from receiving more effective treatments.
He added: ‘While medicinal cannabis may help some conditions such as epilepsy or chronic pain, the evidence for depression, anxiety or PTSD is extremely weak, and patients should be cautious.’
Experts have warned that medicinal cannabis, prescribed privately to thousands of Britons for conditions such as anxiety and depression, may not actually work
The study also highlighted that most clinical trials used oral formulations under supervision, which may differ significantly from the high-THC strains supplied by private clinics.
Freedom of Information data shows 88,214 unlicensed cannabis products were prescribed privately in the first two months of 2025. In total, 659,293 prescriptions were issued in 2024 – equivalent to almost ten tons of cannabis – up from 282,920 in 2023, according to the NHS Business Services Authority.
Data from Mamedica, one of the UK’s largest private clinics, shows 50.5 per cent of its more than 12,000 patients are prescribed cannabis for mental health conditions. Some clinics also offer free consultations or cut-price prescriptions for benefits claimants.
Dozens of specialist pharmacies now offer strains with THC content above 30 per cent, with the total volume prescribed jumping from 2.7 million grams in 2022 to 9.8 million grams in 2024. Products above 22 per cent THC accounted for almost half of all prescriptions in the first two months of 2025.
Sir Robin Murray, professor of psychiatric research at King’s College London, said: ‘There are no randomised controlled trials showing that cannabis benefits psychiatric disorders and a lot of evidence that it causes them.
‘It’s a bit like taking alcohol for depression – some people find it helps in the short term, but in the long term it makes things worse.’
The NHS lists hallucinations and suicidal thoughts among the possible side effects of medical cannabis.
Earlier this year, the family of Oliver Robinson, 34, claimed medical cannabis had contributed to a tragic outcome. After just one video consultation with a private clinic, he developed a £1,000-a-month addiction and an 18-month spiral that ended in his death.
Mr Robinson, an ex-property developer from Bury, Greater Manchester, had previously battled depression, anxiety, bipolar disorder and suicidal thoughts, and had received NHS treatment including antidepressants. He also began using cannabis prescribed online.
