Medical cannabis linked to spike in psychosis presentations


By Geir O'Rourke

23 Feb 2024

The recent dramatic rise in medical cannabis prescriptions within Australia is feeding a surge in hospital presentations for psychosis, a leading psychiatrist is warning.

Research from Associate Professor Stephen Parker, psychiatrist and clinical lead at Brisbane’s Metro North Hospital and Health Service’s early psychosis service shows one in 10 people referred to his services had recently been prescribed medical cannabis.

In each case, the patient had been using prescribed products containing high concentrate tetrahydrocannabinol (THC) in the preceding three months, he reported with colleagues in Australian Psychiatry (link here).

Concerningly, two of these patients continued to obtain prescriptions after the onset of psychosis, while four received a de novo prescription for high-concentrate THC after psychosis onset, according to the report.

“Our opinion is that these prescriptions complicated the treatment and recovery from the first episode of psychosis,” they wrote.

“We regularly have conversations with consumers and their families about the increasing public perception of medicinal cannabis as a harmless panacea being contrary to our clinical experience working at an early psychosis service.”

“There is a concerning lack of regulation allowing consumers to source medicinal cannabis, often from interstate online prescribers, without comprehensive assessment.

Indeed, two-thirds of patients seen had obtained their prescriptions through online services, without having received a face-to-face consultation with the prescriber, they noted.

The authors said the surge underscored the need for reform in medical cannabis regulation, saying urgent efforts were required to ensure evidence-based prescribing that achieved therapeutic benefit rather than iatrogenic harm.

“There is a growing need for enhanced public awareness about the risks and benefits of medicinal cannabis for young people as well as people experiencing mental illness in general,” they added.

AMAQ president Maria Boulton said there had been growing concern from members, particularly as prescriptions soared with more than 700 different products now on the market including oils, tablets, lozenges and creams.

The fact that it was being prescribed for conditions on the basis of extremely flimsy evidence was particularly worrying, given the potential risks, she said.

“We need the federal and state governments to work together, as the current controls do not appear to be working to prevent harm. We need federal action from the TGA to review these products,” she told the Courier Mail (link here).

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