Claims about the therapeutic potential of the CDB are omnipresent online. The WHO, World Health Organisation, like others, has confirmed the good safety profile of the CBD, which presents no risk of abuse. More and more people around the world are asking their doctors whether CBD could be a useful treatment for them. From capsules and oils to topical creams and oral sprays, the craze for CBD has taken off.
However, a recent study by Cannabis Health suggests that medical cannabis treatments rich in CBD alone result in only modest improvement in symptoms.
Does the evidence for the effectiveness of CBD support the hype?
LIMITED EVIDENCE OF SYMPTOM RELIEF
Cannabidiol, or CBD, is the main cannabinoid present in hemp, and is generally the second most common cannabinoid in the cannabis plant. More recently, under the Canadian Medical Cannabis Access Program, cannabis varieties and medical cannabis products have been developed to contain mainly CBD, although traces of THC and other cannabinoids are present.
CBD is known for its antiepileptic and anxiolytic effects supported by clinical and pre-clinical evidence. Several studies have also shown anti-inflammatory, immunomodulatory, antipsychotic and neuroprotective effects. However, the mechanisms of CBD’s effects remain poorly understood and the lack of evidence supporting many of its potential therapeutic properties is proving to be a barrier to its clinical use.
Seizures associated with refractory epilepsy are the symptoms for which there is the most evidence to support the use of CBD. Epidiolex®, the first CBD-based pharmaceutical product, was approved by the US Food and Drug Administration (FDA) in 2018 as an anticonvulsant for the treatment of Lennox-Gastaut syndrome and Dravet’s syndrome. It was also approved by the European Medicines Agency in 2019, but is not currently available in Canada.
The results of 5 randomized controlled trials also suggest moderate evidence that CBD can help reduce the symptoms of psychosis.
Although the evidence supporting CBD as an anxiolytic is limited, Cannabis Health clinicians have observed good results using CBD-rich treatments to relieve anxiety symptoms. A recent increase in the number of high quality, long-term studies on CBD and anxiety may offer more conclusive results in the coming years. Nevertheless, mental disorders such as anxiety currently only account for about 6% of patient cases in Santé Cannabis.
There is also limited evidence that CBD could be used as a treatment for withdrawal symptoms and cravings associated with substance use disorders.
CBD vs CBD and THC
The popularity of CBD has increased in part due to its good safety profile and the fact that it does not cause the psychoactive effects generally associated with THC.
These characteristics have, to some extent, helped to create the impression that CBD has greater medical and therapeutic value than THC. In some countries, the authorities have even launched programmes for access to cannabis for medical purposes that rely exclusively on CBD treatment plans.
However, the most recent clinical study by Santé Cannabis suggests that CBD-rich treatments actually produce only limited improvements in symptom management, compared to treatment plans that combine both CBD and THC.
In some contexts, the use of THC may sometimes be necessary for patients to derive more benefit from their medical treatment with cannabis.
The Cannabis Health study was to be presented at the annual symposium of the International Society for Cannabinoid Research and will be published later this year.
It was conducted with patients who began medical treatment with cannabis in one of our four clinics in Quebec between 2017 and 2019. The study followed two groups during this period: a group of 715 patients who were prescribed treatments rich in CBD and a group of 380 patients who were prescribed both THC and CBD treatments.
Treatment efficacy was assessed using a standardized medical questionnaire and validated assessment tools such as the Edmonton Symptom Assessment Scale (ESAS), Brief Pain Inventory (BPI) and EQ5D at baseline (BL), as well as a follow-up at 3 months (PUP1) and 6 months (PUP2).
The study found that patients whose treatment plan relied solely on CBD-based products reported fewer improvements and benefits than those who incorporated both THC and CBD into their treatment. The group of patients who received both CBD and THC showed a greater improvement in almost all the items assessed, by a statistically and clinically significant margin.
Additional data and further investigation are still needed to further validate these results and to control for potential bias.
In the meantime, in the absence of results from other studies, it is probably best to approach the CBD craze with caution and perhaps a dose of scepticism. However, Cannabis Healthy remains eager to continue clinical research on the subject in cooperation with other participants in the scientific, pharmaceutical and medical fields of cannabis.