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further reaction to Billy Caldwell and the use of cannabis oil for treatment-resistant epilepsy

The comments below follow on from the rapid reaction we sent out yesterday.


Prof Leslie Iversen, former Chair of the Advisory Council on the Misuse of Drugs, said:

“There seems to confusion over the meaning of the term “cannabis oil”. In certain states in the USA where cannabis has been legalised, cannabis oil refers to highly concentrated form of the psychoactive ingredient THC. In Britain, however, cannabis is oil is a solution containing the non-psychoactive compound cannabidiol, thought to have nutritional value and medically as a potential anti-epileptic. Cannabis oil could be sold legally in this country, provided it contained less then 0.05% THC. The Medicines & Healthcare Products Regulatory Agency (MHRA) recently announced, however, that it would be illegal to sell cannabidiol as a medicine without completing the onerous clinical testing and safety assessment required of new medicines.

“It is perhaps ironic that a British company (ML Laboratories) is developing a herbally derived preparation of cannabidiol (“Epediolex”) as a treatment for childhood epilepsy.”


Prof Deb Pal, Professor of Paediatric Epilepsy, Institute of Psychiatry, Psychology & Neuroscience at King’s College London, said:

“There is now good evidence from clinical trials conducted in the US and Europe that pharmaceutical preparations of cannabidiol are effective against two types of severe childhood epilepsy known as Dravet syndrome and Lennox-Gastaut syndrome. These types of epilepsy are often resistant to conventional antiepileptic drugs. The evidence from these trials has only recently been published and both the FDA in the USA and the EMA in Europe will now consider the evidence in order to grant a licence for the drug to be used in clinical practice. If successful then the drug would become available to prescribe for named patients towards the end of the year or early next year.

“All new medications need to be thoroughly evaluated for reasons of patient safety, effectiveness and economics. This applies just as much to cannabinoids as to any other pharmacologically active product, perhaps more so given the huge publicity surrounding the medical marketing of cannabis-derived products. It’s important to realise that the trial evidence is for pharmaceutically manufactured medicines, not over the counter preparations that may not have been produced to the same standards or with different components. Nor does it necessarily follow that cannabinoids will be safe and effective for other types of epilepsy. Thus we need to follow the usual processes for new drug approval such as NICE appraisal, otherwise we risk patient safety if we respond to every demand on a case-by-case basis.”


Prof Celia Morgan, Professor of Psychopharmacology, University of Exeter, said:

Are you convinced there is solid evidence that cannabis oil actually works? Is there a scientific consensus on this?

“Trials have largely focused on pharmacological preparations, but the active ingredients in Billy’s cannabis oil are the same as those tested in trials which have been shown to be effective in humans e.g. THC and CBD. As a result of research and clinical experience, cannabidiol has been given a special drug designation by the Food and Drug Administration in the US for the treatment of childhood epilepsy – which I would say is evidence that a scientific consensus exists.”

Is there a good evidence base for THC working for epilepsy?

“Whilst the bulk of current research underway concerns CBD, there are reported instances of the cannabis plant being used to treat epilepsy dating back four millennia and more recently reviews of human and animal evidence conclude that THC also may have anti-convulsant properties. And indeed other cannabinoids in the plant, such as cannabidivarin, have been similarly found to be anticonvulsant. We don’t know how many more there may be. All this research, however, has been hampered by the legal status of the drug which is, in my opinion, why the field is not more advanced.”

Is there good evidence that other illnesses would benefit from the CBD and THC in cannabis oil?

“There is good evidence that these drugs work in a number of other conditions too. Some examples are that THC works in reducing nausea, and stimulating appetite in HIV and cancer, there is evidence from inflammatory bowel disease, Tourette’s and that it may be effective in pain, CBD reduces anxiety and may have anti-psychotic and anti-addictive properties, and there is preliminary evidence in other conditions such as cancer. The problem is as always that due to the legal status research has been more limited than the scope of medicinal uses of this plant might suggest.”

At the moment the conversation is about legalising a cannabis product as a treatment, how problematic are the regulations around research, or should the two things not be conflated?

“The regulations around research are tricky, there is more red-tape around conducting these studies and some clinical trials units are not keen to research cannabinoid products. We were told to run a study at a different hospital because we wanted to run a trial of a cannabinoid. And it is not only regulations but also clinical and patient opinion of these drugs that can be difficult to work with, people in general have an idea of cannabinoids as recreational drugs and not as powerful medicines.”

Are there other illegal drug products, with the same level of evidence as cannabis for epilepsy, that work for other illnesses and should be considered for legalisation as medicines?

“Drugs such as LSD, MDMA and ayahuasca are emerging as powerful adjuncts to psychological therapies for mental health problems like depression, trauma and addiction. The evidence base is growing at the moment but soon it will be unjust to withhold access to these medicines for these patients.”

Do you have any other points that the public or authorities need to be considering now?

“We currently lag behind the rest of the world in our use and research of cannabinoid medicines. We have an important opportunity in the UK to learn from the experience of introducing medical cannabis in other countries. It seems a crucial time to introduce a more progressive legislation that means that children like Billy are able to access the most effective medicines for their conditions, determined by evidence, not legal status.”


Declared interests

None received


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