Medicinal cannabis is causing harm to some patients, with doctors warning of a significant increase of people ending up in hospital with psychosis after being prescribed the drug.
Their concerns come amid a proliferation of "single-issue" cannabis clinics setting up in Australia, some of them willing to prescribe via telehealth consultations with few checks.
Brett Emmerson, Queensland chair of the Royal Australian and New Zealand's College of Psychiatrists, says the college wants stronger regulations of medicinal cannabis products and prescribing practices.
"We're seeing a lot of people getting medicinal cannabis who end up with their first psychotic episode, or we're seeing it dispensed to people who have psychotic conditions, and these people are relapsing," Professor Emmerson says.
"Part of the issue … are these single-issue clinics which, if you ring up, it doesn't matter what you say you want.
"They'll provide it for you even though there is probably no indication that it will work, and the prescribers never contact the person's treating doctor.
"You find out two or three months down the track that one of your patients has been on medicinal cannabis — not prescribed by you but by some other prescriber — usually a doctor who hasn't had the professional courtesy of contacting you and letting you know."
A lot of prescriptions happening over the internet
Professor Emmerson says Queensland's Metro North Health — Australia's largest public health service, based in north Brisbane and the surrounding region — is seeing increased presentations of psychosis due to medicinal cannabis.
"The Metro North early psychosis service reports 10 per cent of their new presentations — so these are kids aged 16 to 21 — are people who've ended up on medicinal cannabis and are becoming psychotic," the Brisbane-based psychiatrist says.
"A lot of other mental health services are reporting several admissions a week of people who have been placed on medicinal cannabis who shouldn't be on it.
"Medicinal cannabis is causing harm. The medication is unregulated, and it's being used widely for a whole range of conditions for which there is no evidence."
Jennifer Martin, a Newcastle-based general physician and clinical pharmacologist, says apart from triggering psychosis in some patients, hospital emergency departments are also seeing people presenting with a condition called cannabis hyperemesis syndrome after taking medical cannabis.
"That's when you throw up a lot when the potency is too high," Professor Martin, who is also the President of the Royal Australasian College of Physicians, says.
"Some of these products have a lot of very psychoactive product in them.
"These are big problems for our hospital system, because those people sit in the emergency department [and] they potentially take up a bed for a long period of time."
Professor Martin, of the University of Newcastle, says a lot of medicinal cannabis prescriptions are being done on the internet, via "a web interaction or telehealth".
"It's actually very difficult to get access to the doctor that actually signed the script for a patient," she says.
What is medical cannabis prescribed for?
Medicinal cannabis was legalised in Australia in 2016.
Some products are based on the compound cannabidiol, or CBD, but others also contain tetrahydrocannabinol, or THC, the psychoactive ingredient in cannabis.
Professor Emmerson says the two most common reasons medicinal cannabis is prescribed are for anxiety and insomnia.
"There's no evidence that medicinal cannabis is helpful or treats those conditions," he says.
"Treatment for anxiety, and often insomnia, is cognitive behavioural therapy from a good psychologist.
"Getting people hooked on a drug of dependence when there are other non-drug treatments available, and haven't been accessed, is wrong.
"The medicinal cannabis industry is marketing and making claims that cannabis can cure a whole range of different medical conditions and there's just no evidence for it."
Professor Emmerson likened medicinal cannabis companies to alcohol and tobacco retailers who "want people to end up on their product for their profit".
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