THE DOWNSIDE OF GETTING HIGH IN B.C.

Tyler Ridout was smoking a lot of marijuana. Three or four joints a
day. That was not unusual, even for a high school kid. Nor was it
remarkable that he thought the pot was good for him, a natural stress reliever.

In fact, it was influencing his moods and his behaviours. It was
making him sick. Mr. Ridout was experiencing psychosis. He began to
think there were dragons in his parents' yard. He could not shake the
feeling that the world was about to end. His mother Debbie called a
government-sponsored drug hotline, looking for help. "I was told not
to worry, that it's just pot and not that big a deal," she recalled
this week. Her son wound up in a hospital psychiatric ward.

Ben Nixon also used to smoke a lot of pot in high school. He too
became psychotic. He was sure he had seen a troll in the forest, a
slithering anaconda in the house, and other creatures. Mr. Nixon
spent a year in hospital. "I constantly thought about cutting off my
tongue," he told a group of junior high school students in North
Vancouver this week.

The two young men were made ill by so-called B.C. bud, a catch-all
term for locally grown marijuana. Thanks to intensive breeding
programs and sophisticated growing techniques, it's as potent as any
in the world. It's not the mild, giggle-producing, appetite-enhancing
pot you might remember. That stuff no longer exists. Today's pot is a
different drug, with five to eight times more psychoactive
Tetrahydrocannibinol (THC) than good old Acapulco Gold. And 130% more
potent than marijuana produced just a decade ago. Despite what some
of its advocates might claim, any "medicinal" qualities are bred
right out of the stuff that's sold on the streets. It's not wacky
anymore. It's dangerous.

Mr. Ridout and Mr. Nixon both know that. They ' ve come forward to
share their nightmarish stories in a new documentary by Vancouver
filmmaker Bruce Mohun. The Downside of High airs tonight on CBC's The
Nature of Things. It's a chilling program, but not some hysterical
Reefer Madness piece of work. Mr. Mohun is not a marijuana
prohibitionist. He decided to make the documentary after Mr. Ridout,
his nephew, became seriously ill.

The documentary relies on modern inquiry and new research that's
slowly getting attention outside of scientific communities.
London-based schizophrenia and cannabis expert Robin Murray describes
how scientists in Europe have been able to connect marijuana use to
mental illness. In the meantime, some opinion makers, even
governments and health authorities, have helped perpetuate the myth
that it is relatively safe.

"The frequency of cannabis consumption and the resultant psychosis in
the U.K. is among the highest in Europe," Dr. Murray noted last year
in a Guardian newspaper guest editorial. "The government's mistake
was . to give the impression that cannabis was harmless and that
there was no link with psychosis. Charles Clarke, the then Home
Secretary, realized the error in 2005 and promised education and research."

It might seem a bit late. "It is estimated that at least 10% of all
people with schizophrenia in the U.K. would not have developed the
illness if they had not smoked cannabis," noted Dr. Murray, "so there
are about 25,000 individuals whose lives have been ruined by cannabis."

Downplaying the damage that marijuana can cause is counterproductive.
"What we need," Dr. Murray says in the documentary, "is a situation
where people know that if you smoke cannabis heavily, particularly if
you smoke potent brands of cannabis, then you're more likely to go psychotic."

But therein lies another problem. Most pot smokers don't know what
they are inhaling. Except for unusual cases, their marijuana is
illicitly produced, purchased and consumed. There are no regulations
that control its production, no quality controls and standards, no
ingredient and warning labels. Users don't know the source of the
product, or its chemical content, or its potency. In other words,
smoking pot is akin to drinking a stranger's bathtub gin. To anyone
susceptible to mental illness, more hazardous.

This could buttress an argument for marijuana legalization. The
Downside of High doesn't venture there; the film is focused on the
science. And it says the most effective damage control strategy is to
give people the truth.