SECOND THOUGHTS ABOUT MARIJUANA

Vancouver Sun columnist Ian Mulgrew recently bemoaned Justice Minister
Irwin Cotler's failure to speak up on behalf of Marc Emery, British
Columbia's "Prince of Pot" and self-described benefactor-cum-martyr to the
cause of marijuana legalization. Mr. Emery is facing charges in the U.S.
for alleged money laundering and marijuana-related conspiracies. Worse,
during a press conference, it appeared the minister was disavowing Bill
C17, which will see tickets issued for simple possession of marijuana.

"Anyone who thought this former law professor was going to usher in an era
of reform in the criminal prohibition against pot should read the writing
on the wall," Mr. Mulgrew lamented.

It is the justice minister who is reading the writing on the wall -- the
wall in Europe, that is, where politicians are having second thoughts about
prematurely liberalized marijuana laws. In Britain, for instance, Home
Secretary Charles Clarke is reviewing legislation that reclassified
cannabis as a less-serious drug, while in Holland, health minister Han
Hoogervorst is reconsidering state involvement in the sale of medical
marijuana and the reclassification of high-potency "skunk" marijuana.

Why these changes of heart?

This column previously discussed the work of a handful of British, Dutch,
Swedish and New Zealand scientists who established connections between
adolescent use of marijuana and the development of psychosis and
schizophrenia. Their studies were cited by both Mr. Clarke and Mr.
Hoogervorst but it is the Head of Psychiatry at King's College Institute of
Psychiatry, pre-eminent authority and co-editor of Marijuana and Madness
(published in 2004), Robin M. Murray, who first raised awareness on this
subject. Working with patients in South London, and as lead or co-author of
many of these studies, he also issued public warnings about the dangers of
cannabis and the failure of the British government to consult experts in
psychosis before reclassifying marijuana.

I spoke with Mr. Murray earlier this year. Many of the issues we discussed
were subsequently raised during his interview with BBC television's current
affairs program Panorama. An edited transcript is available online;
paraphrased highlights follow:

* Schizophrenia, a severe form of psychosis, affects patients from
childhood. Though cannabis has been used for thousands of years, it was
during and after the 1960s that consumption of cannabis with increasingly
high potency by increasingly younger users accelerated. By the early 1990s,
more patients displayed psychotic symptoms despite having had normal
childhoods. Cannabis use by such patients suggested a connection that led
to recent research. Since the 1960s, incidence of schizophrenia has doubled
in south London.

* Psychosis results from an excess of dopamine, the pleasure/perception
chemical. The resulting chemical imbalance can cause a heightened sense of
self-importance, anxiety, memory loss and ultimately paranoia. Cannabis,
like alcohol and amphetamines, revs up dopamine, hence its usefulness for
people in pain. In most people dopamine just gives pleasure; in others it
can produce psychosis.

* Of those who become psychotic, genetic susceptibility is a factor. The
COMT gene, consisting of an MET type and a VAL type, metabolizes dopamine.
A MET/VAL mixture increases risk of psychosis from cannabis twofold. A
VAL/VAL mixture increases the risk 10 times. A quarter of the population is
VAL/VAL, a quarter is MET/MET and the rest is a mixture.

* Studies of large adolescent cohorts indicate that those who take a lot of
cannabis are more likely to develop psychosis. The earlier the consumption,
the bigger the risk. While dependency is also a possibility, the more
worrying possibility is that since changes in the dopamine receptors occur
in the developing adolescent brain, early cannabis use may permanently
alter it.

For instance, it is known that the neuronal system of adolescent rats given
a range of drugs from cocaine to amphetamines to cannabis becomes
permanently altered.

Mr. Murray is agnostic about marijuana legalization. Education, he says, is
the key. In Britain, he told me, the pro-legalization lobby accepts
cannabis as a factor in psychosis.

What does this mean for marijuana law reform in Canada? Until an updated
national drug strategy is in place, Bill C17 must simply be shelved.

Current decriminalization and legalization advocacy fails to distinguish
between recreational use among sophisticated adults and the clear and
present risk to adolescent users.

Since adolescents will obtain cannabis anyway, this risk will not disappear
under legalized adult use while decriminalization merely provides a green
light for adolescents to continue use.