Limiting youth access to high-THC cannabis products such as "shatter" is a key to reducing the risk of harm as marijuana legalization looms in this country, according to the Canadian Centre on Substance Abuse.

"From a public health perspective we're really concerned with minimizing the risks associated with youth," Rebecca Jesseman, the senior policy advisor for the centre, told On the Island host Gregor Craigie.

"That includes key messages such as delaying initiation of use, reducing frequency of use, and reducing the quantity of use," Jesseman said. "Part of that is quantity in terms of concentration too."

The CCSA, which is mandated to reduce the harms of alcohol and other drugs, examined post-legalization issues in the states of Washington, Colorado and Oregon.

Jesseman's comments followed an interview this week with Dr. Kiri Simms, an emergency psychiatrist in Victoria.

Dr. Simms said she's seen an increase in the number of patients experiencing psychosis after using powerful marijuana-derived products such as shatter. 

Young patients obtain 'shatter' easily

Simms said she has personally seen 10 patients in the past year "very, very ill and with the kind of psychotic experience that requires a stay in our psychiatric intensive care or on one of our in-patient wards."

They include young patients who told her they can easily obtain shatter and other butane hash oil products at local medical marijuana storefront businesses.

The interview and web story prompted a flood of Facebook comments — mainly negative — most rejecting any link between shatter and psychosis. 

CBC Victoria facebook 'shatter' reaction

An interview with an emergency psychiatrist describing psychosis among users of the drug 'shatter' evoked mainly negative responses.

Simms' concerns about the use of shatter and similar products comes as the Canadian Paediatric Society urges the federal government to prohibit cannabis sales to anyone under 18 or 19.

The position statement also recommends limiting the concentration of THC  — the main psychoactive component that provides pot's high — in cannabis sold to 18- to 25-year-olds.

"Cannabis can produce an acute/transient psychosis in adolescents, even without a history of prior mental illness," the pediatric society's statement said. 

The CCSA does not recommend banning high-THC products such as shatter, Jesseman said, but she agrees strong rules are needed.

Tax it, don't ban it

"Unfortunately if you prohibit higher concentrates and there's still a market demand, then that means you're quite potentially feeding an illegal market in order to meet that demand," she said.

An alternative might be using pricing to limit access to products like shatter.

"We know that the people most likely to use some of these stronger THC products tend to be fairly price sensitive," she said. "It's younger adults, mostly males, who tend to not necessarily have the same amount of disposable income.

"So things like differential taxation, making sure that the higher THC products simply cost more, therefore promoting the use of lower THC products, is one strategy we can look at," Jesseman said.


To hear the full interview with Rebecca Jesseman on CBC Radio One On the Island go to Use of high-potency cannabis products by youth raises health concerns.