A professor of psychiatry has called for more debate on the use of medicinal cannabis in mental health after warning of a spike in anxiety cases triggered by Covid-19.

David Castle, a professor at St Vincent’s Hospital in Melbourne, stressed the need for Australia to “advance the science” around both cannabis and psychedelic medicine.

He revealed that Covid has sparked a wave of patients with anxiety issues, many of whom get no respite from conventional medicines.

During a discussion on mental health and cannabis at the recent Australian Symposium of Medical Cannabis, panellists spoke of a need for a personalised approach to cannabinoids and for closely monitored experimentation.

David Castle - Lastest Cannabis News - Cannabiz
Psychiatry professor David Castle has predicted a further rise in psychiatric cases following the Covid pandemic

There was also a clear message not to confuse the effects of recreational cannabis on mental health with that of medicinal cannabis prescribed by health practitioners.

Speaking at the symposium, organised by the Australian Institute of Medical Cannabis, Castle said: “We absolutely have to recognise there is huge ongoing morbidity within the general population in terms of psychiatric disorder. PTSD is one and there is no doubt we are going to see that increase after Covid.

“Goodness knows how many people I am seeing who are increasingly anxious and not able to sleep at night… and for whom conventional medicines do not work.

“I’m not saying cannabis should be put in the drinking water, or is the answer for everyone, but we need to be open to this and advance the science.”

Australia has been on the “back foot” regarding science and needs to “step up and open the debate and availability”, Castle said.

He continued: “These are not dangerous compounds. There are some concerns about particularly vulnerable individuals who are using high THC, but we know what is in medicinal compounds and you can make informed decisions with the patient around which compounds you use.

“I’m not saying put cannabis in the drinking water, or is the answer for everyone, but we need to be open to this and advance the science.”

professor of psychiatry david castle

Castle called on “true life and real patient” examples to be recognised and explored.

“This sort of stuff… is the most powerful messaging,” he said.

GP Jamie Rickcord, founder and director of Byron Bay-based Ananda Clinics, echoed Castle’s remarks, and stressed discussion around the effects of recreational and medicinal cannabis must be clearly defined.

“There needs to be a push both for cannabinoids and psychedelic medicine,” he said. “This is for medicinal use with trained professionals, and with evidence to back it up.

Dr Jamie Rickcord - Medical Cannabis Australia - Cannabiz
Dr Jamie Rickcord: “We’re not promoting people buy marijuana from the hills.”

“We are not talking about going to festivals or promoting that people buy their marijuana from the hills. They are two separate things and we need to keep hammering that message home. Once people understand that, it’s going to improve for everyone.”

Rickcord suggested that psychedelic medicine in particular sends people “running away”. But he predicted the take up could be faster than cannabis once laws start to change.

“The evidence for psychedelics is probably more overwhelmingly positive than some of the evidence for cannabinoid medicine,” he said.

Earlier in the discussion, Rickcord said more doctors need to start prescribing medicinal cannabis if Australia is to learn how patients with mental health issues respond to various formulations of cannabinoids.

And for that to happen there may need to be a change in regulations which currently require GPs to identify a specific condition before they can prescribe cannabis product.

Asked for his views on the benefits of isolates and full-plant products, Rickcord said: “It’s an ongoing debate about isolates verses full plant, but anecdotally most patients prefer full-plant products.

“We are in the early stages of understanding it in Australia and we need more doctors with bigger numbers than possibly exist at the moment to start teasing out what’s working and what’s not, and that’s based on personal experience.

“If you’re talking hard evidence of what’s going on, that is some way away and it’s expensive.”

Australian Institute For Medical Cannabis - Medical Cannabis - Cannabiz
The symposium was the first such event held by the Australian Institute for Medical Cannabis, in conjunction with Cannatrek

Castle said while his experience is “limited”, CBD seems “really helpful” for some people with sleep and anxiety issues.

He suggested an individualised DIY approach, in consultation with a prescribing doctor, could unlock the right cannabinoid balance.   

“With pain syndrome for example you do need some THC so it’s a bit of a balancing act,” he said. “Patients can actually do this themselves. They can get CBD and THC rich oil and mix and match which I think is not a bad way forward if you’re closely monitoring the efficacy.”    

Jerome Sarris, professor of Integrative Mental Health at the NICM Health Research Institute, said patients are often taking cannabis for a variety of symptoms and disorders. Yet under the Special Assess Scheme, medicinal cannabis must be prescribed for a specific disorder.

“There is obviously a major focus on pain, anxiety, insomnia and some mood management, that is what people are mainly using for, so a lot of the time they are not using it for one particular symptom,” he said.

“But when you get it prescribed you have to focus on a particular disorder, even though that is not how people are using it.”

Sarris cited the example of US psychiatrist Scott Shannon who prescribes CBD for children with insomnia and trauma.

“But I don’t know that’s something that could be prescribed via our system because maybe it doesn’t meet the threshold of a particular disorder,” he said. “Hopefully we’ll move towards having a greater understanding in terms of a flexible approach, and how CBD is actually being used and accepting that… rather than it being disorder specific.”

Jerome Sarris - Latest Cannabis News - Cannabiz
Jerome Sarris: The same product can work differently with each patient

Sarris added that it was important to understand “the interface from a personalised medicine perspective about the range of cannabis compounds and preparations”.

“We are not quite there yet, but that data is evolving,” he told the symposium. “We have to consider how does that relate to a person’s individual genetics? How does that relate from a pharmacogenomics perspective and from an individual’s traits, their psychological state?

“Some products may work really well for one person, but not someone else. It might not be down to the products, it’s to do with the individual. We are learning about that interface more and more, but it will take a bit of time to get more understanding.”

Emily Rigby, research program director at Cannatrek, agreed that medicinal cannabis can be a personalised medicine given the way it interacts with our own endocannabinoid system.

“It’s very much like our fingerprint, it’s unique,” she said.

Asked how to address personalised medicine, Castle said it was best to approach it in the manner the name suggests.

“Listen to the patient,” he said. He described the ability to find the right formulation as an “art form”.

“With PTSD for example… listen to patients and ask what symptoms they are most troubled by. A lot of people with PTSD hate the night because they know they’re not going to sleep and they know they’re going to have terrible nightmares. So it’s often about the anxiolytic and soporific effects [of medicinal cannabis].

“Others have been through physical trauma and have pain syndrome and you need to target that separately. It really is a bit of an art form so personalised medicine is mainly listening to the patient.”

Rickcord said he treats PTSD with higher doses of CBD. But with the right amount of THC patients can enter a more “parasympathetic place”.

“With antidepressants or benzos, patients say it numbs them, and disconnects them from themselves. But if we use the right amount of cannabinoids we can regulate them without disconnecting from their emotions,” he explained.

“That way their symptoms are resolving and that’s what we’re doing, we’re improving their well-being.

“That is personal medicine, and that is individual for every single patient. You can’t go wrong if you start with fairly big doses of CBD and slowly increase the THC until you find the sweet spot. And then their lives improve.”

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