Meanwhile, we believe potentially 100,000 Australians are using cannabis to treat their medical conditions but because this is illegal, the true scale of this use is unknown. Such illicit use risks prosecution and all the complications that come with using an illegally sourced drug of uncertain composition. Cannabis-using "criminals" include thousands of people with severe, unrelenting pain who have reached the end of the line on the prescription opioid express. It includes children with intractable epilepsy and people with painful neurological conditions, for whom cannabis has transformed their quality of life. Concerns with cannabis usually revolve around the adverse effects of THC – the main psychoactive ingredient. While such effects are still hotly debated in scientific circles, it is increasingly clear that many diseases can be treated by cannabis products that have little, if any, THC. Many types of cannabis, including industrial hemp, contain little THC but are enriched in other cannabinoids such as cannabidiol, which have anti-epileptic, anti-anxiety, antipsychotic, anti-inflammatory and other therapeutic effects.

And there is no need to smoke. Cannabis products now come in myriad forms, including oils, lozenges, sprays, lotions, patches and capsules. An initial problem facing Australian patients seeking medicinal cannabis is that their GPs often know very little about it, and unlike Canada, where GPs can write you a script, a sympathetic Australian GP must enlist the support of a specialist to apply to the TGA for cannabis products. And even if a specialist is available, and sympathetic, they are probably not covered by their insurer when prescribing cannabis products to patients. Let's assume your medical practitioners are courageous: the next step is a detailed application to the TGA outlining the scientific evidence showing that cannabis can treat your condition more effectively than conventional prescription meds. This leads to the stoush over "the evidence".

Earlier this year, the US National Academies of Sciences, Engineering and Medicine released a comprehensive review medicinal cannabis. Evidence for the efficacy of cannabis in some diseases is sparse due to the historical barriers preventing clinical trials of cannabis products. But absence of evidence, as Carl Sagan said, is not evidence of absence. The NASEM report still gave resounding support for the use of cannabis products for pain, for nausea and vomiting in people receiving chemotherapy, for spasticity in multiple sclerosis, and for various forms of insomnia. But in Australia, the TGA is reluctant to approve the use of cannabis for the conditions for which it is most commonly used in the community: pain, insomnia and PTSD/anxiety. So the TGA will grant access to patients with less common conditions – such as multiple sclerosis and intractable epilepsy – but not to the 20 per cent of Australians suffering from chronic pain.

Even if your specialist can convince the TGA that your condition is treatable with cannabis products, your mission is still incomplete. Your specialist/GP must also apply to their state or territory health department for further approval. This involves more form-filling and delay. And when you finally have all your ducks in a row, there is the not-so-small issue of cost. The TGA-approved products available to patients are extremely expensive. It may cost $120 a day to obtain cannabis products to treat a child with pediatric epilepsy, with no subsidy available from the Pharmaceutical Benefits Scheme. Putting it all together, it becomes clear why only 250 or so Australians have access to officially sanctioned medicinal cannabis products. In striking comparison, Canada has more than 200,000 officially approved patients, and Israel more than 30,000.

Admittedly, it is early days in Australia and profound change does not happen overnight. Yet the design of the Australian system seems to almost guarantee its failure. There are several steps that could be taken to better meet community expectations: an amnesty for current users of illicit cannabis products with verified medical conditions would be a good start. Allowing appropriately trained GPs to prescribe medicinal cannabis products without specialist involvement would also help, as would dispensing with the need for duplicate state approvals. Rescheduling of non-intoxicating, low-THC cannabis products as over-the-counter medicines might also be considered. When manufactured according to best practice, these products are no more hazardous than many of the nutraceuticals on pharmacy shelves. Loading

Let's rethink our strategy and make medicinal cannabis products readily available to Australians in need. Professor Iain McGregor is academic director of the Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney.