The numbers tell an extraordinary story. In just four years, more than one million prescriptions for medicinal cannabis have been approved in Australia. Sales have tripled. More than 700,000 Australians have reported using it to treat close to 300 different health conditions. Yet according to new research from the University of Sydney, a significant portion of these prescriptions may be helping patients very little, and possibly causing harm.
The study, led by Dr Jack Wilson at the Matilda Centre, found no evidence that medicinal cannabis is effective at treating anxiety, depression, or post-traumatic stress disorder. This is significant because anxiety disorders account for the largest share of medicinal cannabis prescriptions for psychiatric conditions. Researchers are now asking a pointed question: should these medicines be approved to treat these conditions at all?
The concern goes beyond the absence of evidence. Wilson and his team point to real risks. "The routine use of medicinal cannabis could be doing more harm than good by worsening mental health outcomes," Wilson said in a statement about the research. This could manifest as a greater risk of psychotic symptoms, development of cannabis use disorder, or a delay in accessing more effective treatments like antidepressants or cognitive behavioural therapy.
The pattern reflects how Australia's medicinal cannabis system works in practice. Since 2016, when the government legalised access for medical purposes, doctors have been able to prescribe unregistered cannabis products through what is called the Special Access Scheme. A doctor applies to the Therapeutic Goods Administration on a case-by-case basis. Approval often comes within 24 to 48 hours. Only two cannabis products have been formally registered as proper medicines: nabiximols for multiple sclerosis and cannabidiol for certain types of childhood epilepsy. Everything else exists in a regulatory grey zone.
The research does acknowledge that some conditions may benefit from medicinal cannabis. The evidence for autism, insomnia, and Tourette's syndrome is more promising. However, Wilson stressed that even in these cases, the quality of evidence remains low, and "in the absence of robust medical or counselling support, the use of medicinal cannabis in these cases are rarely justified."
Interestingly, medicinal cannabis is not effective for all substance abuse disorders either. When prescribed for people with cocaine addiction, it actually increased cravings. This underscores a broader tension in Australia's medicinal cannabis landscape: prescribing has expanded rapidly while the evidentiary base has not kept pace.
For patients seeking mental health treatment, the gap between what people hope medicinal cannabis might do and what evidence actually supports is substantial. A 2023 review of Australian prescribing patterns found that anxiety disorders accounted for the largest number of psychiatric approvals. Yet the same literature that review cited noted very limited evidence for cannabis as an anxiety treatment, with some analyses showing no effect once publication bias was corrected for.
The question now is whether Australia's regulatory framework can catch up to prescribing reality. The Therapeutic Goods Administration operates under the assumption that doctors will exercise professional judgment. Yet when the approval process is fast and the public interest is high, that judgment may be stretched. The TGA itself has noted that most medicinal cannabis products are unapproved goods that have not been assessed for safety, quality, or effectiveness.
Researchers are now calling for greater regulation. The concern is not with medicinal cannabis in principle; it is with prescribing practices that have outpaced evidence. For mental health conditions in particular, the evidence suggests a more cautious approach is warranted. Patients deserve treatments that work, backed by solid research. Until that evidence exists for anxiety and depression, faster approvals may simply mean faster roads to ineffective care.