Cannabis oil â€“ which, when produced for medical purposes, contains carefully controlled amounts of the cannabinoids cannabidiol (CBD) and tetrahydrocannabinol (THC) â€“ continues to be the subject of much debate. In 2018, medical cannabis became legal in the UK after a nationwide outpouring of support for two young boys who rely on cannabis oil to treat their severe and rare forms of epilepsy, but lingering concerns around the safety and efficiency of the medicine mean that access is still heavily restricted.
Here, Health Europa highlights two recent pieces of research which are adding to the evidence base on the therapeutic benefits of cannabis oil.
Cannabis oil significantly improves both the symptoms of Crohnâ€™s disease and patientsâ€™ quality of life, but, contrary to previous medical thinking, does not affect inflammation in the gut.
This is according to a first-of-its-kind, randomised controlled study by researchers in Israel, who enrolled 46 people with moderately severe Crohnâ€™s disease â€“ a type of inflammatory bowel disease â€“ and treated them with either a placebo or cannabis oil containing 15% CBD and 4% THC.1
The researchers measured participantsâ€™ symptom severity and quality of life before, during and after treatment using validated research instruments, and assessed inflammation in the gut endoscopically and by measuring inflammatory markers in blood and stool samples.
â€śCannabis has been used for centuries to treat a wide range of medical conditions, and studies have shown that many people with Crohnâ€™s disease use cannabis regularly to relieve their symptoms,â€ť explains lead researcher Dr Timna Naftali, a gastroenterology specialist at Meir Hospital and Kupat Holim Clinic.
â€śIt has always been thought that this improvement was related to a reduction in inflammation in the gut, and the aim of this study was to investigate this.â€ť
The results were surprising: after eight weeks of treatment, the group receiving cannabis oil had seen a significant improvement in their quality of life and a substantial reduction in their symptoms compared to the placebo group. 65% of the former met strict criteria for clinical remission, compared to just 35% of the latter.
However, these improvements did not seem to be caused by a suppression of the underlying inflammatory process.
â€śWe have previously demonstrated that cannabis can produce measurable improvements in Crohnâ€™s disease symptoms, but, to our surprise, we saw no statistically significant improvements in endoscopic scores or in the inflammatory markers we measured in the cannabis oil group compared with the placebo group,â€ť explains Naftali.
â€śWe know that cannabinoids can have profound anti-inflammatory effects, but this study indicates that the improvement in symptoms may not be related to these anti-inflammatory properties.â€ť
As a next step, the researchers aim to investigate in more detail the potential anti-inflammatory properties of cannabis as a treatment for inflammatory bowel disease.
â€śThere are very good grounds to believe that the endocannabinoid system is a potential therapeutic target in Crohnâ€™s disease and other gastrointestinal diseases,â€ť Naftali says.
Until then, she adds, cannabis oil should only be considered an â€śalternative or additional intervention that provides temporary symptom relief for some people with Crohnâ€™s diseaseâ€ť.
In a separate study also from Israel, cannabis oil has been shown to relieve symptoms in children and young people with autism spectrum disorder (ASD).
Researchers at Ben-Gurion University of the Negev (BGU) and Soroka University Medical Center analysed data prospectively collected as part of the treatment programme of 188 under-18-year-olds with ASD who were treated with medical cannabis â€“ primarily cannabis oil containing 30% CBD and 1.5% THC â€“ between 2015 and 2017.2
Structured questionnaires were used to assess the primary outcomes of interest: symptoms, patient global assessment, and side effects at six months.
The results were impressive. After six months of treatment, 30% of patients reported a significant improvement, 53.7% reported a moderate improvement, and just 15% reported a slight or no change.
The effect of the cannabis oil on quality of life, mood, and ability to perform daily tasks was also significant:
â€śOverall, more than 80% of the parents reported significant or moderate improvement in their child,â€ť says Lihi Bar-Lev Schleider, of the BGU-Soroka Clinical Cannabis Research Institute.
These results suggest that cannabis is a well-tolerated, safe and effective option for the relief of autism symptoms, including seizures, tics, depression, restlessness and rage attacks, in under-18-year-olds.
However, according to Dr Victor Novack, also of the BGU-Soroka Clinical Cannabis Research Institute: â€śDouble-blind placebo-controlled trials are crucial for a better understanding of the cannabis effect on ASD patients.â€ť
Research such as that highlighted above will be vital if countries and health policymakers are to open up access to cannabis oil and other forms of medical cannabis, which, despite increasingly favourable legislation, remains understudied.
Please note, this article will appear in issue 9 of Health Europa Quarterly, which will be available to read in April 2019.