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Evidence shows ‘promise’ for medical cannabis in mental health

In a new book, Professor Kylie O’Brien discusses cannabis and its role in mental healthcare



illustrating Mental health
Professor Kylie O’Brien on cannabis and its role in mental health

In a new book, Professor Kylie O’Brien PhD, discusses the evidence behind medical cannabis and a range of mental health conditions, to help clinicians prescribe safely.

Professor Kylie O’ Brien had carved an impressive academic and medical career, in her home country Australia, before moving into medical cannabis. She joined Releaf Group in 2020 where she now works as chief scientific officer and this year launched the International College of Cannabinoid Medicine (ICCM Ltd), an international online education platform providing educational resources on medicinal cannabis for healthcare practitioners.

As an internationally recognised expert in Chinese medicine, integrative medicine and medical cannabis, she is now due to release her second book,O’Brien & Blair, Medicinal Cannabis and CBD in Mental Healthcare: Springer, 2021.’

Mental Health: A banner advert for the medical cannabis clinics

The motivation behind it, she says, was to combine colleague Dr Philip Blair’s “clinical experience” with scientific evidence which would provide a “level of rationale” for healthcare practitioners to consider medicinal cannabis, so they don’t dismiss it.

Some of the different conditions discussed in the detailed clinician’s guide include autism spectrum disorder, insomnia, anxiety, depression, PTSD and Alzheimer’s disease. It examines how CBD, or THC, could be used to benefit different mental health conditions.

Mental health conditions increase

It couldn’t be released at a better time. Post-lockdown mental health statistics are rising as the world struggles to cope with Covid. According to the Office for National Statistics, by the middle of 2020, one in five people in Britain had depression. This was double the 2019 figure. Diagnosis of conditions such as Autism is also on the rise. The British Medical Association estimates that 700,000 people in the UK have a diagnosis of autism.

O’Brien said that there is a need for more education in medicinal cannabis that has strong evidence to back it up.

Mental Health: A portrait of author and Dr Kylie O' Brien

Professor Kylie O’Brien

“There is a need for more education and to actually put evidence behind it,” she said. “The reason we wrote this book on medicinal cannabis and CBD in mental health care is that a lot of doctors don’t know there is robust evidence.

“The book looks at six different conditions including anxiety, depression, PTSD, insomnia, Alzheimer’s disease and autism spectrum disorder. A lot of doctors want to know how safe cannabis is. The top reason for using medical cannabis is usually chronic pain and the second is typically anxiety. We need to educate healthcare practitioners about the level of evidence that exists as well as where there are gaps.”

There are limited studies when it comes to CBD, or even THC, and mental health. Some studies suggest that CBD may affect serotonin levels or that it may have an effect on the receptors located in the brain. A recent study into Alzheimer’s Disease showed CBD treatment increased levels of IL-33 and TREM2, sevenfold and tenfold, respectively. Proteins TREM2 and IL-33 are important to the ability of the brain to consume dead cells and other debris like the beta-amyloid plaque that piles up in patients’ brains, both of which are reduced in Alzheimer’s patients.

Mental Health evidence

While more evidence is needed, what’s out there so far is promising.

“In terms of two main mental health conditions of anxiety and depression, there is stronger evidence for the efficacy of medicinal cannabis for anxiety disorders but less for depression, ” O’Brien explained.

“There is a range of evidence that CBD and in some cases THC may also be helpful in various mental health conditions. There are cross-sectional studies on people with PTSD, particularly war veterans who use cannabis and self-medicate many of their symptoms with it,” she said.

She added: “There is a growing amount of clinical trials now to test this out in a real sense. The evidence is mixed but there is certainly enough to show there is promise.”

It’s also important to consider the real-world evidence. O’Brien and Blair have included case studies throughout the book, derived from Dr Blair MD’s clinical practice, which can be extremely powerful tools in demonstrating to doctors the benefits of this treatment. While clinical trials studies can often have narrow inclusion criteria or not allow for co-morbidities, the personal touch of adding patient stories can teach doctors a lot about how a condition reacts to individual dosage amounts or ratios.

She explained: “You can often get narrow inclusion criteria for clinical studies and strict exclusion criteria so that you can only really generalise results to people who have similar characteristics. That’s the limitation of randomised control trials. Doctors often learn from case studies. I think that is a valid form of evidence that often gets relegated further down the pyramid of evidence in medicine when it really shouldn’t.”

But O’Brien stressed also that prescribers are right to be cautious, with some studies showing higher levels of THC may have mental health concerns, though this is often dose-related.

“You can look into the research and find that high levels of THC can be associated with anxiety and other mental health issues. The cultivated varieties of cannabis bred for the recreational market have been bred to have very high amounts of THC. The negative side effects of THC are typically dose-related,” she continued.

“A lot of the literature around safety and negative effects of cannabis is associated with recreational use. You have to bring it into context. That is not to say that cannabis medicines won’t have side effects in some people at certain doses. It’s another reason why these should be prescribed by a healthcare practitioner who is trained in cannabinoid medicine,” she said.

Mental healthcare professionals

If healthcare professionals are not willing to prescribe, patients may choose to access the medicine illicitly, which could put them at greater risk of harm on the black market.

“An advantage of people going to a healthcare practitioner trained in medicinal cannabis is that they can get valuable advice on dosing,” said O’Brien.

“If you are looking into oils, the ones on the legal market that are prescribed by doctors have good quality control. When you buy products on the grey or black market then you don’t know what you are getting.

“It is always a concern that you could have some contamination in cannabis medicines available on the grey or black market. I always advise people to get it prescribed because of that quality control.”

In Australia, O’Brien feels that doctors are becoming more comfortable prescribing for mental health conditions. However, this is not always the case in other countries where there may be more stigma or less education around the benefits of cannabis.

“Our doctors trained in medicinal cannabis are comfortable prescribing for mental health conditions and there is more demand for it,” she said.

“A lot of doctors become more comfortable with it as their knowledge base and clinical experience grows, it gives them confidence.”

But the stigma hasn’t gone away entirely.

O’Brien said: “Many people don’t understand how it is used in medicine or its value or therapeutic actions. “It brings it back to why education is so important.”

It was this that inspired her to set up the ICCM, to bring together clinical experts in medicinal cannabis from across the world to improve knowledge and ultimately patient access.

“You need to hold your beliefs for a moment and look at some of the evidence to get a different appreciation of it. I think there is still a stigma attached to it and I think, like a lot of things that have been demonised over a long time period, it is going to take time to shift that.”



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