The high and lows of medicinal cannabis
Associate Professor Jon Lane
Chief Psychiatrist
Department of Veterans’ Affairs
“Natural, plant-based medicine”, or are there other concerns?
Medicinal cannabis (MC), has been growing in popularity both in Australia and overseas over recent years. There are many reasons for this, but also a significant number of concerns. This can be seen in the large increase in media reports about the harms that have occurred when care isn’t taken in prescribing these drugs.
The questions are: Should we be concerned? And what is DVA going to do about it?
MC refers to a cannabis product that is used to treat a medical condition. It is regulated by the Therapeutic Goods Administration (TGA), but not actually approved (more on this later), unlike most medicines prescribed by your doctor. MC products come from the cannabis plant used for a range of different health conditions. The best-known active ingredients are THC (Δ-9-tetrahydrocannabinol) and CBD (cannabidiol).
THC is psychoactive and causes the “high”. It is responsible for most of the problems with MC, including the side effect of psychotic disorders, which involve being disconnected with reality, such as seeing things that aren’t there or hearing voices. It can also cause dependence in up to one in 4 people, when people need to keep taking it or get withdrawal symptoms if they stop. It is also very common to need to increase amounts to get the same effect as before, which is known as tolerance.
CBD doesn’t give a high. It is the ingredient that may decrease pain, inflammation, and anxiety.
Products vary widely (oils, flower, gummies, sprays), and how much THC or CBD it contains can be very different too. This means the side effects can vary.
The evidence of benefits from MC is still very mixed: at best, they tend to be small rather than dramatic, including for chronic pain.
DVA primarily funds MC for chronic pain, however, we also cover it for chemotherapy-induced nausea, palliative care, anorexia and wasting associated with chronic health conditions.
DVA does not fund MC for mental health conditions because there is no good evidence of benefit, but there is significant risk of harm when MC is co-prescribed with other mental health medications, and significant risks of developing new conditions such as psychosis. Treatment of mental health conditions with MC therefore doesn’t fit with our priority of supporting the wellbeing of veterans.
There have been many different media reports about the harms from MC, particularly because while these products are being prescribed in greater frequency and strengths, they are still not actually approved. This means they have not been checked for safety, quality and consistency of the product or usefulness in treating your symptoms by the TGA. This is different to other prescriptions from your doctor or over the counter medicines like paracetamol from the pharmacy.
A recent ABC news report (TGA yet to investigate the safety of most medicinal cannabis products) demonstrated these concerns and described ‘615 reports made to the TGA involving unregistered medicinal cannabis products between 1 July, 2022 and 1 June, 2025’.
A lot of people might think that MC is “natural” and therefore mostly harmless, and this is reinforced by MC marketing. Unfortunately, this isn’t true because MC can have significant side effects and can negatively interact with other prescribed medicines.
Bad side effects reported include psychosis, suicide, and poisoning – including from children and pets finding “gummies” or lolly-like preparations and ending up in comas.
As a result of increasing concern about the harms of MC from medical bodies, the Australian Health Practitioner Regulation Agency (AHPRA) has been investigating some MC prescribers and MC prescribing practices. It recently reported concerns with “single purpose dispensary” business models that could lead to unsafe prescribing. One concerning finding was that just 8 prescribers wrote more than 10,000 scripts in less than 6 months, reflecting both the demand for MC and the concentration of providers.
Marketing of MC is also problematic, with University of Queensland academics finding that ‘around 47% of the clinics were classified as being in ‘High Breach’ by breaching at least 2 TGA (advertising) guidelines’. It also reported that ‘most breaches occur under guideline 1, which often involved providers displaying images of cannabis plants or logos, referencing industry awards or using abbreviations for cannabinoids. A frequent breach involved unsubstantiated claims about the benefits of cannabis for health conditions.
These forms of marketing are concerning because they are designed to make the drug attractive and minimise the inherent risks.
If you have any interest in any medicine, the best thing you can do is talk to your trusted GP about it, rather than rely on advertising, whether it is MC, a weight loss drug, or any other kind of medicine.
MC is now big business. The Pennington Institute’s Cannabis in Australia, 2024 report stated that the total number of units sold in the first half of 2024 reached 2.87 million, up considerably from the 1.68 million units sold in the second half of 2023. It put the dollar value of this as being over $400 million, so this equates to nearly a billion dollars last year and likely much more in 2025. There are serious dollars being spent on MC in Australia.
DVA funds MC for only 5% of veterans, but veterans are definitely a target market for these businesses. Veterans have reported inappropriate advertising on social media, as well as direct marketing through other means.
In my role as DVA’s Chief Psychiatrist, my concerns about MC are about how DVA can protect veterans’ mental health and functioning, while still providing access to something that has really helped some veterans.
As a part of the move to nationally recognised best-practice models, and supporting good medical practice with minimal restrictions, we are preparing guidelines for the safe use of MC – this includes when it’s appropriate to start, how to monitor and when it’s appropriate to stop. This move is in line with best-practice medicine and the practices of other countries such as Canada, and will be part of further work across the Department in the coming months to address the issues identified here.