Cannabis and brain tumours
The potential therapeutic effects of cannabis have gained a lot of attention in recent years, from both brain tumour patients and within the media.
Two of Brain Tumour Research’s Member Charities have now joined forces to launch a study into the clinical effects of cannabidiol (CBD), the non-psychoactive ingredient in cannabis. The research, builds upon previous research in this area and will be conducted by the Children’s Brain Tumour Research Centre at the University of Nottingham, and is being co-funded by the Astro Brain Tumour Fund and other brain tumour foundations.
The calls for research into the effectiveness of cannabis-based treatments have not just been prompted by a growing number of brain tumour patients and researchers, but also by Parliamentarians.
In the run-up to the General Election, Baroness Meacher, Co-Chair of the All-Party Parliamentary Group on Drug Policy Reform has called for a relaxation of the rules around cannabis-based medicines. It has been noted how cannabis can also provide symptomatic relief to patients with various conditions, and it is licensed for the treatment of multiple sclerosis.
We have analysed the evidence for the use of cannabis as a potential treatment for brain tumours.
Are there any cannabis-based drugs available?
Sativex was rigorously tested for its safety and efficacy before receiving approval, and is distinguished from cannabis in its raw form by its specific components. The composition, formulation and dose have been developed to provide medicinal benefits with minimal psychoactive effects.
Other sources include cannabis oil (CBD), which is legally available in the UK, and the cannabis plant, which is illegal within the UK and in about half of the US States with other States’ laws broadly legalising marijuana in some form. The plant also has limited availability in some European countries, albeit under strict control.
Is there any evidence for the clinical benefit of cannabis?
Clinical studies have recently been carried out to assess the potential benefit of Sativex when given in combination with temozolomide (TMZ). Although the interim results of the trial appear to be promising, we need to wait for the complete data before any specific conclusions can be drawn.
At the moment, it is permissible for a UK doctor to prescribe Sativex “off-licence” i.e. as a treatment for a condition for which it has not been approved. This would be at the discretion of the clinician, who must carefully consider the evidence that is available for the clinical benefit of the drug in addition to any potential adverse effects.
Furthermore, some patients may have to pay for the cost of the medication and it is unlikely that the cost would be reimbursed by private health insurance due to it being prescribed off-licence.
Are there any benefits from taking cannabis oil?
Some people have used cannabis oil as a potential treatment for their brain tumour; it contains the non-addictive CBD component of cannabis.
The oil is currently marketed as a health rather than a medicinal product which means that different regulations apply. The manufacturers are not permitted to make any claims about the efficacy of the agent for the treatment of specific medical conditions. Although the product is made in accordance with general manufacturing guidelines to ensure that it is safe, there is no independent quality testing to confirm the amount of compound present in the product, despite what may be stated on the label. This unreliability makes it difficult to assess whether there are any health benefits.
Once claims are made about the benefit of the cannabis oil (or other healthcare products) for specific medical conditions, it now comes under medicinal (rather than health) product guidelines and therefore has to undergo clinical trials in the same way as any other medicine before it can be made available (https://www.gov.uk/government/news/mhra-statement-on-products-containing-cannabidiol-cbd). This is likely to be by prescription rather than as an “over the counter” product. Furthermore, the quality testing would be much more rigorous in order to confirm the exact components present in the oil.
So what are the next steps?
It may be possible to allow limited use in the clinic when the larger trial is taking place, but this would be at the discretion of the regulatory authorities and is likely to be very controlled for a restricted group of patients who are most likely to benefit.
In the meanwhile, we will keep a close eye on all developments in the area, and keep you updated of all developments in future blogs.
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Study: CBD From Marijuana May ‘Reset’ The Brain To Counteract Symptoms Of Psychosis
Cannabidiol (CBD), the non-intoxicating compound in marijuana, continues drawing attention as a potential treatment for disorders and illnesses ranging from epilepsy to cancer. Now a new brain imaging study suggests that a single dose of CBD can reduce symptoms of psychosis by “resetting” activity in three brain areas. If replicable, the study offers the first evidence-based explanation for how CBD works in the brain to counteract psychosis, with results that could help generate new treatments.
Psychosis is not a single condition or disorder, but is rather a symptom of other disorders characterized by detachment from reality. Seeing, hearing or believing things that aren’t real, including hallucinations, is typical of a psychotic episode. While the exact causes of psychosis aren’t known, it’s thought to be triggered by mental illness, trauma, substance abuse and extreme stress. Even lack of sleep can spark an episode.
While psychosis is most often associated with schizophrenia, it actually affects a much larger segment of the population. At least 100,000 people a year experience their first onset of psychosis in the U.S., according to the National Institute of Mental Health.
This was a small study of 33 participants who were experiencing psychotic symptoms. A smaller group of healthy participants served as a control group. Half the psychosis group was given one 600 mg oral dose of CBD (a dose that was “previously effective in established psychosis” according to the study), the other half received an identical placebo capsule. The control group didn’t receive any drug. Then all of the participants completed a memory task designed to engage three brain areas that have been linked to the onset of psychosis (specifically the striatum, medial temporal cortex, and midbrain) while their brains were examined with an fMRI scanner.
The scans showed abnormal activity in the brains of the participants experiencing symptoms, as compared to the healthy control group – that much was expected. But the brains of those who had taken a dose of CBD showed less severe abnormalities than the brains of those who had taken a placebo, suggesting that the compound was “resetting” abnormal activity in the key brain areas.
“The results have started unravelling the brain mechanisms of a new drug that works in a completely different way to traditional anti-psychotics,” said the study’s lead author Dr. Sagnik Bhattacharyya from the Institute of Psychiatry, Psychology & Neuroscience at King’s College, London.
The study did have limitations. Aside from being a small study with a methodology unable to account for every factor that might influence the outcome, the researchers also noted that they can’t be sure the results weren’t caused by “the rapid changes in cerebral perfusion that are known to occur with a single dose of psychoactive drugs.” In other words, they may have witnessed a short-term effect that won’t last. Quoting from the study: “It is also unclear whether the effects of CBD will persist after longer-term dosing.”
The next step, already underway, is a large-scale human trial to replicate the results and determine if CBD is a viable treatment. If successful, the drug would be immediately differentiated from other meds on the market—including some that have been around since the 1950s—that produce inconsistent results. Some of the most common meds also have notoriously severe side effects, including muscle tremors and overpowering sedation.
“There is an urgent need for a safe treatment for young people at risk of psychosis,” added Dr. Bhattacharyya. “One of the main advantages of cannabidiol is that it is safe and seems to be very well tolerated, making it in some ways an ideal treatment.”
The study represents another move forward for CBD as a treatment for brain-based disorders. Earlier this year, the US FDA approved the first drug comprised of CBD to treat severe forms of epilepsy. While CBD derived from cannabis is a Schedule 1 controlled substance under federal law in the US, hemp-derived CBD is more widely accessible, though its legality in terms of federal law is still murky at best.
Members of this research team conducted an earlier study showing that CBD seems to counterbalance the effects of tetrahydrocannabinol (THC), the psychoactive compound in marijuana that gets users high. THC has been linked to the onset of psychosis in some users and appears to mimic aspects of psychosis in the brain. If CBD turns out to be an effective anti-psychotic, these findings will highlight yet another striking paradox of a plant that science is only now really beginning to understand.