Where is the evidence?
Updated: Nov 12, 2019
In the United Kingdom, CBD is primarily sold as a food supplement. Food supplements are expressly forbidden from making any sort of medical or health claims regarding their active ingredients. This has led many to believe that CBD has no place in medical products, which is completely untrue. Not only are there multiple medical products containing CBD currently available, but there are also dozens of clinical trials underway to prove which of CBD's effects are also suitable for the treatment of medical conditions. These trials range from investigating CBD's effects on anxiety disorders, neuropathic pain and arthritis, among others. A total of 209 clinical trials involving CBD are listed on the clinicaltrials.gov website, the majority of which are completed and have results available.
Something interesting to note: approximately a quarter of all studies are backed or sponsored by GW Pharma. This itself is unsurprising, considering that they were the first company in the world to fully license a medical product containing Cannabidiol: Sativex. Sativex was licensed in 2010 for use in patients with Multiple Sclerosis to alleviate neuropathic pain, spasticity and other symptoms of MS. It consists of a 50/50 ratio of THC/CBD. Because of this mix of cannabinoids it is classed as a Class B controlled drug under the Misuse of Drugs Act 1971 and is only available on prescription by a specialist doctor with experience treating MS.
GW Pharma also have a second medical product containing CBD: Epidiolex. Epidiolex was only approved in 2018 for the treatment of epileptic symptoms in patients with Dravet or Lennox-Gastaut syndrome, aged 2 years or older. Unlike Sativex, Epidiolex consists purely of Cannabidiol. Aside from the greater ease of access due to CBD's less strict legal restriction compared to THC, the total dosage of active ingredient is much higher in comparison. Sativex is an oral spray that delivers 2.7mg of THC and 2.5 mg of CBD per spray, whereas Epidiolex is an oral syringe-delivered oil that delivers 100mg of CBD per ml, with a recommended starting dose of 5ml. The suggested total dose for Epidiolex is 10mg/kg of body mass per day, although if required one may take up to 20mg/kg per day.
So we can see that CBD has definite potential as a medical product, especially in the treatment of neurodegenerative disorders. From the number of clinical trials both currently underway and completed, it is clear that many pharmaceutical/research companies have understood this potential of CBD as a medicine. Disregarding its ability to alleviate symptoms of epileptic syndromes and MS, the number of applications that CBD has in regards to treating various ailments is impressive. There are results available from studies investigating the effects of CBD on ulceratic colitis, pain relief in patients with advanced cancer or neurological pain.
With this in mind, why then are there so few clinical trials compared to the number of scientific studies on the matter of CBD? A quick search on Google Scholar for these studies involving the term “cannabidiol” turns up nearly 40,000 results – even removing patents and citations. While some of these will be repeats or passing mentions, that's still considerably more papers than clinical trials. One reason is the stringency with which clinical trials are regulated. Another is the cost and length of time clinical trials require. A large scale Phase III trial (the phase looking into the efficacy of a potential medicine on its targeted demographic) can be anything from several hundred thousand pounds to potentially tens of millions. When considered in conjunction with the fact that they often take up to a year to complete, it makes sense that it requires the resources of a considerable-sized pharmaceutical company to carry out.
Despite the intimidating entry requirements to begin clinical trials for a medicine, funding , grants and incentives from the EMA and similar regulatory bodies, in conjunction with increasing knowledge of CBD and acceptance from governments and health agencies, means that we're likely to see more and more medical products that include CBD in some aspect. Personally, I wouldn't be surprised to see either an anti-anxiety or pain relief medication within the next few years. Regardless of your opinion on cannabinoids, the creation of new medical products can only be a positive for the many people they will end up helping.