More Australians than ever are being prescribed medicinal cannabis .
Authors
- Suzanne Nielsen
Professor and Deputy Director, Monash Addiction Research Centre, Monash University
- Myfanwy Graham
NHMRC Postgraduate Scholar and Fulbright Alumna in Public Health Policy, Monash University
Medicinal cannabis refers to legally prescribed cannabis products. These are either the plant itself, or naturally occurring ingredients extracted from the plant. These ingredients, such as THC (tetrahydrocannabinol) and CBD (cannabidiol), are called cannabinoids. Some cannabinoids are also made in labs to act like the ones in the plant.
Medicinal cannabis comes in different forms, such as oils, capsules, dried flower (used in a vaporiser), sprays and edible forms such as gummies.
Since regulatory changes in 2016 made medicinal cannabis more accessible, Australia's regulator has issued more than 700,000 approvals . (But approvals for medicinal cannabis don't reflect the actual number of patients treated. One patient may have multiple approvals, and not all approved products are necessarily prescribed or supplied.)
Around half of the approvals have been for chronic pain that isn't caused by cancer.
In Australia, chronic pain affects around one in five Australians aged 45 and over, with an enormous impact on people's lives.
So what does the current evidence tell us about the effectiveness of medicinal cannabis for chronic pain?
What the evidence shows
A 2021 review of 32 randomised controlled trials involving nearly 5,200 people with chronic pain, examined the effects of medicinal cannabis or cannabinoids. The study found a small improvements in pain and physical functioning compared with a placebo.
A previous review found that to achieve a 30% reduction in pain for one person, 24 people would need to be treated with medicinal cannabis.
The 2021 review also found small improvements in sleep, and no consistent benefits for other quality of life measures, consistent with previous reviews .
This doesn't mean medicinal cannabis doesn't help anyone. But it suggests that, on average, the benefits are limited to a smaller number of people.
Many pain specialists have questioned if the evidence for medicinal cannabis is sufficient to support its use for pain.
The Faculty of Pain Medicine , the professional body dedicated to the training and education of specialist pain physicians, recommends medical cannabis should be limited to clinical trials.
What does the regulator say?
Guidance from Australia's regulator, the Therapeutic Goods Administration (TGA), on medicinal cannabis for chronic non-cancer pain reflects these uncertainties.
The TGA states there is limited evidence medicinal cannabis provides clinically significant pain relief for many pain conditions. Therefore, the potential benefits versus harms should be considered patient-by-patient.
The TGA says medicinal cannabis should only be trialled when other standard therapies have been tried and did not provide enough pain relief.
In terms of which type of medical cannabis product to use, due to concerns about the safety of inhaled cannabis, the TGA considers pharmaceutical-grade products (such as nabiximols or extracts containing THC and/or CBD) to be safer.
What about people who say it helps?
This evidence may feel at odds with the experiences of people who report relief from medicinal cannabis.
In clinical practice, it's common for individuals to respond differently based on their health conditions, beliefs and many other factors. What works well for one person may not work for another.
Research helps us understand what outcomes are typical or expected for most people, but there is variation. Some people may find medicinal cannabis improves their pain, sleep or general well-being - especially if other treatments haven't helped.
What are the side effects and risks?
Like any medicine, medicinal cannabis has potential side effects . These are usually mild to moderate, including drowsiness or sedation, dizziness, impaired concentration, a dry mouth, nausea and cognitive slowing.
These side effects are often greater with higher-potency THC products. These are becoming more common on the Australian market. High-potency THC products represent more than half of approvals in 2025 .
In research studies, generally more people experience side effects than report benefits from medical cannabis.
Medical cannabis can also interact with other medications , especially those that cause drowsiness (such as opioids), medicines for mental illness, anti-epileptics, blood thinners and immunosuppressants.
Even cannabidiol (CBD), which isn't considered intoxicating like THC, has been linked to serious drug interactions.
These risks are greater when cannabis is prescribed by a doctor who doesn't regularly manage the patient's chronic pain or isn't in contact with their other health-care providers. Since medicinal cannabis is often prescribed through separate telehealth clinics, this fragmented care may increase the risk of harmful interactions.
Another concern is developing cannabis use disorder (commonly understood as "addiction"). A 2024 study found one in four people using medical cannabis develop a cannabis use disorder. Withdrawal symptoms - such as irritability, sleep problems, or cravings - can occur with frequent and heavy use.
For some people, tolerance can also develop with long-term use, meaning you need to take higher doses to get the same effect. This can increase the risk of developing a cannabis use disorder.
How does it compare to other treatments?
Like many medicines for chronic pain , the effectiveness of medicinal cannabis is modest, and is not recommended as a sole treatment.
There's good evidence that, for conditions like back pain, interventions such as exercise, cognitive behavioural therapy and pain self-management education can help and may have fewer risks than many medicines.
But there are challenges with how accessible and affordable these treatments are for many Australians, especially outside major cities .
So where does this leave patients?
The growing use of medicinal cannabis for chronic pain reflects both a high burden of pain in the community and gaps in access to effective care. While some patients report benefits, the current evidence suggests these are likely to be small for most people, and must be weighed against the risks.
If you are considering medicinal cannabis, it's important to talk to your usual health-care provider, ideally one familiar with your full medical history, to help you decide the best approaches to help manage your pain.
Suzanne Nielsen receives funding from the Australian National Health and Medical Research Council, alongside government and philanthropic organisations to conduct independent research.. She is the president-elect for the Australasian Professional Society on Alcohol and Other Drugs. She serves as a consultant for the World Health Organization. She has contributed to independent reviews of the evidence on medical cannabis for government organisations include Worksafe and the TGA.
Myfanwy Graham receives funding from the Australian National Health and Medical Research Council, alongside government and university institutes. Myfanwy has served as a consultant for the UNODC, WHO and NASEM. She is an appointed member of the Therapeutic Goods Administration's Medicinal Cannabis Expert Working Group. This article does not represent the views of the TGA or the Expert Working Group.
