Pubdate: Wed, 13 Sep 2017
Source: London Free Press (CN ON)
Copyright: 2017 The London Free Press
Author: Dale Carruthers
Page: A1


Londoners may have found way to reverse THC's psychiatric

Western University researchers may have found a way to reverse the
harmful effects that marijuana use can have on teenagers' brains.

The researchers, in a breakthrough discovery, say they've found a way
to use pharmaceutical drugs to counter the long-term negative
psychiatric effects of tetrahydrocannabinol (THC), the psychoactive
component in cannabis that gives users the feeling of a euphoric high.

Previous research has linked chronic pot use by teens with a range of
psychiatric diseases such as schizophrenia later in life, with the
risk rising the earlier that young people begin using marijuana.

The Western discovery's announcement comes days after Ontario became
the first province to detail its plans to sell legal marijuana next
year, deciding pot will be sold through a separate arm of the
province's LCBO liquor store monopoly and - significantly, for teens -
its sale limited to buyers 19 and older, just like booze and cigarettes.

The Western study, published Tuesday in Scientific Reports,
demonstrated adolescent THC exposure affects the neurotransmitter
called GABA, a chemical messenger previously associated with
schizophrenia, in the brain's prefrontal cortex.

The seven-member research team found that when GABA was reduced by THC
exposure in adolescence, neurons in that region of the brain became
hyperactive and out of synch, resulting in an abnormal state in the
dopamine system that's commonly seen in schizophrenia.

Using drugs to activate GABA in rats, researchers reversed the effects
of THC to eliminate the schizophrenia-like symptoms.

"Even after the damage has occurred in adolescence, if can you
effectively target these changes, you can potentially mitigate these
negative symptoms and reverse some of these side effects," said study
co-author Steven Laviolette, an associate professor at Western's
Schulich School of Medicine & Dentistry.

Ontario's plan to sell recreational pot in Ontario calls for a
subsidiary of the Liquor Control Board of Ontario (LCBO) to begin
selling marijuana at 40 outlets - orders also will be taken online -
by next summer, when the federal Liberals are expected to deliver on
their vow to liberalize Canada's pot laws and make recreational use
legal. A task force had recommended 18 be the minimum age to buy
marijuana, but provinces have free rein to raise the age

Pot's potential to have lasting psychiatric effects continues into a
person's mid-twenties, said Laurent Marcoux of the Canadian Medical

"There is a high risk because the human brain develops until 25,"
Marcoux said, adding not enough is known about the long-term effects
of cannabis to introduce the drug for recreational use.

"It's like 50 years ago with cigarettes," he said.

Laviolette, who first started researching cannabis 13 years ago, said
red tape often gets in the way.

"Even the non-psychoactive compounds found in marijuana are listed as
narcotics, so you need to get licences, you need to get exemptions,"
he said. "I think it scares a lot of people away from actually
conducting these studies."

And then there's the struggle to source pure THC.

Despite the federal government's plan to legalize recreational pot by
July 1, 2018, Laviolette has to order THC from the U.S., paying around
$2,000 a gram for the substance - significantly more than the $10 a
gram for which pot sells on the street.

"It can be done, but it's prohibitive," Laviolette said of obtaining
pure THC.

Lavilette and his research team now will turn their focus to exploring
how combinations of cannabinoid chemicals as a potential treatment for
addictions and mood disorders such as depression and anxiety.
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