A systematic review of 30 studies from the United States, Canada and Thailand shows legalising cannabis is associated with increased rates of cannabis poisoning.
Experts say those most at risk are children.
A team from the University of Sydney says cannabis exposures in children are of particular concern with “potential for severe toxicity, including coma, neurological and cardiovascular effects.”
The findings come as the Therapeutic Goods Administration announces a crack down on unlawful medicinal cannabis advertising, and follows the introduction of bills to legalise marijuana for personal use in parliaments in Victoria, New South Wales and Western Australia.
Medicinal marijuana was made legal in Australia in 2016.
The meta-analysis published in Addiction finds cannabis poisonings among all people increased after legalising medicinal and recreational use by a ‘pooled estimate’ of 3.56. This means there were 3 to 4 times higher rates of cannabis poisoning following legalisation.
University of Sydney clinical pharmacologist and study author Professor Nicholas Buckley says cannabis poisoning is generally accidental, and “the ones we worry about most are small children”.
He says, the study shows poisonings are commonly associated with edible forms of cannabis.
Along with greater access to very strong cannabis in a form which looks like lollies, the effects of edible cannabis are delayed, meaning children or young people may ingest an extremely high dose before they feel unwell.
He says this should be the focus of regulatory protections to avoid poisonings and incidental harm in Australia. This might include childproof packaging, prohibiting advertising, ensuring cannabis cannot be made to look like confectionary and protections to avoid products being sold to children.
“A lot of the serious cases in the literature are when small child eats their parents edibles. People have left these very strong cannabis lollies lying around. And then the kid eats the lollies and becomes quite unwell. So, they can become comatose, they can have seizures, they can just be very confused.”
Buckley’s says people in Australia should think about avoiding some of the mistakes made when cannabis was legalised in the US.
“In particular, allowing marijuana edibles that look like lollies was an obvious mistake that explains much of the increase in poisonings,” he says.
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