Last published: July 19, 2021
Note: The information given on this page is not medical advice and should not be relied on in this way. Individuals wanting medical advice on this issue should consult a health professional.
What is medicinal cannabis?
Broadly speaking, medicinal cannabis is cannabis prescribed to relieve the symptoms of a medical condition, such as epilepsy. It’s important to distinguish between medicinal and recreational cannabis. Recreational cannabis is the form that people use to get ‘high’.1
For some people with chronic or terminal illnesses, conventional medicines don’t work, or don’t work as effectively as medicinal cannabis. Also, for some patients, conventional medicines may work but cause debilitating side effects that cannabis can help to relieve.2
What are cannabinoids?
The main psychoactive ingredient of cannabis is tetrahydrocannabinol (THC), which acts on specific receptors in the brain known as cannabinoid or CB1 receptors.3
Research has found that the cannabis plant produces between 80 and 100 cannabinoids and about 300 non-cannabinoid chemicals. The two main cannabinoids that have therapeutic benefits are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). There have been claims that other cannabinoids have therapeutic properties, but these have not yet been proven.1
The main difference between the two cannabinoids is that THC has strong psychoactive effects, meaning it makes a person ‘high’, whereas CBD is thought to have an anti-psychoactive effect that controls or moderates the ‘high’ caused by the THC. CBD is also thought to reduce some of the other negative effects that people can experience from THC, such as anxiety.4
The psychoactive effects of THC, such as euphoria and feeling relaxed or sleepy, are well known, but it also has analgesic, anti-inflammatory and antioxidant properties, as well as preventing and reducing vomiting.1
Research is being conducted into CBD for its potential to treat epilepsy, schizophrenia and other psychotic disorders, type 2 diabetes, inflammatory bowel disease, some tumours, and drug dependency.1
The endocannabinoid system
The endocannabinoid system is a unique communications system in the brain and body that affects many important functions.5 It’s made up of natural molecules known as cannabinoids, and the pathways they interact with. Together, these parts work to regulate activities like mood, memory, sleep and appetite. It is thought that medicinal cannabis can treat various illnesses by acting on the endocannabinoid system.6
Types and forms of medicinal cannabis
There are three main forms of cannabis that can be used medicinally:
- Pharmaceutical cannabis products that are approved by an organisation such as the Therapeutic Goods Administration (TGA), including nabiximols (Sativex®) and synthetic cannabinoids such as Dronabinol®. Sativex, which comes as a nasal or oral spray, has been approved in over 24 countries for treating spasticity due to multiple sclerosis.
- Controlled and standardised herbal cannabis (plant products), such as the products produced in the Netherlands.
- Unregulated and illegal herbal cannabis (plant products), which contains unknown concentrations of cannabinoids and potentially harmful impurities such as bacteria and mould (USA only).7
Why smoking cannabis for medical purposes is not recommended
Some people claim that smoked cannabis should be considered as a treatment for various medical conditions or even as a cure for cancer. However, there are two major concerns.
Firstly, smoking is a particularly harmful way of taking cannabis, mainly because carcinogenic substances are inhaled directly into the lungs. Smoking cannabis is not recommended by health authorities, as the smoked form contains at least 50 of the same carcinogens as tobacco.8
Secondly, the majority of medicines used in Australia are produced under strict conditions. That way, doctors who are prescribing them (as well as people who are using them) know exactly what’s in them.
It’s important that doctors know that medicines have been tested and that each dose is the same. This means doctors can monitor the effects of a drug and doses can be adjusted according to a patient’s needs.
When recreational cannabis is used as medicine, doctors and patients can’t be sure of how strong it is or what mix of chemicals is in it. Consequently, one dose will never be the same as another.8
There is a community need for medicines and therapies that can help to alleviate the painful symptoms of various illnesses and diseases.
An increasing number of studies suggest that medicinal cannabis in the form of oral extracts, sprays or pills can reduce pain and help treat some illnesses. However, as with many other drugs, medicinal cannabis can also cause unwanted side effects, such as difficulty concentrating, dizziness, drowsiness, loss of balance, and problems with thinking and memory.9,10
Special Access Scheme
Under the TGA Special Access Scheme, some forms of medicinal cannabis are available. The scheme allows the import and supply of an unapproved therapeutic good to individual patients on a case-by-case basis.
Recently, the TGA has made changes to its Special Access Scheme to make it easier for medical practitioners to prescribe cannabis-based medicines for patients in need, under certain conditions.
Legislation that allows cannabis to be grown for medical or scientific purposes in Australia has been passed by the federal government.
In October 2016, the Commonwealth Government started a national licensing scheme for the cultivation and manufacture of medicinal cannabis and controls all its regulatory aspects.
Manufacture is a joint responsibility between the Commonwealth and the states and territories. Access to any cannabis products manufactured under the scheme is also a joint responsibility, with supply controlled by the provisions in the Therapeutic Goods Act 1989, which works in tandem with state and territory drugs and poisons legislation.10,11
- Victorian Law Reform Commission (2015). Medicinal Cannabis. Retrieved from the Victorian Law Reform Commission.
- Rattenbury, S. (2014). ACT Greens Medicinal Cannabis Discussion Paper.
- Hall, W. (2015). US policy responses to calls for the medical use of cannabis. Journal of Biology and Medicine 88: 257-264.
- Mechoulam R. Cannabis—a valuable drug that deserves better treatment. InMayo Clinic Proceedings 2012 Feb 1 (Vol. 87, No. 2, pp. 107-109). Elsevier.
- NSW Parliament. (2000) Report of the Working Party on the Use of Cannabis for Medical Purposes. Sydney: NSW Parliament.
- Scholastic. (2011). The science of the endocannabinoid system: how THC affects the brain and the body.
- Belackova V, Ritter A, Shanahan M, Chalmers J, Hughes C, Barratt M & Lancaster K. (2015). Medicinal cannabis in Australia: framing the regulatory options.
- American Lung Association; Marijuana and Lung Health. [Chicago, United States]: [updated 2015 March 23; cited 2019 March 15].Callaghan, R. C., Allebeck, P., Sidorchuk, A. (2013) Marijuana use and risk of lung cancer: a 40-year cohort study. Cancer Causes Control, 24, 1811–1820.Schwartz, D.A. Int J Ment Health Addiction (2018) 16: 797.
- Therapeutic Goods Administration. (2018). Guidance for the use of medicinal cannabis in Australia: Patient information: The side effects of medicinal cannabis treatment
- Health Department, Australian Government. (2016). Narcotic Drug Amendment Bill 2016 public information paper.
- Parliament of Australia. (2016). Narcotic Drugs Amendment Bill 2016.