LAW AND THE SAFETY OF MARIJUANA REQUIRE A CAREFUL ASSESSMENT

If some of the evidence contained in a recent United Nations
scientific study leads to one conclusion, it is that legal ambiguity
in Canada over the use of marijuana has resulted in a policy vacuum,
while this country's consumption of the drug has risen to four times
the world average.

According to the UN's Office on Drugs and Crime, which produced the
2007 World Drug Report, 16.8 per cent of Canadians aged 15 to 64
smoked marijuana or used a cannabis-related product last year. The
average is 3.8 per cent world-wide. Only four countries - all
non-industrialized - had higher rates than Canada. This country has
the highest rate of marijuana use among industrialized nations.

In the meantime, scientific evidence released this summer suggests
that as many as one in four cannabis users is at risk of coming down
with a serious mental illness, such as schizophrenia or psychosis. The
research, sponsored by Britain's health ministry and published in the
July 28 issue of the medical journal, The Lancet, found that people
who used marijuana had roughly a 40 per cent higher chance of
developing a psychotic disorder.

The risk of developing schizophrenia for most people is less than one
per cent. The prevalence of schizophrenia in the United States is
currently about five in 1,000 people. But because of the widespread
use of marijuana, the researchers estimated that about 800 new cases
of psychosis could be prevented by curtailing its use. They also found
that the risk of psychosis for daily or weekly marijuana users ranged
from 50 to 200 per cent, and that there was a higher risk for people
with a history of mental illness in their families.

While some (such as Ottawa Citizen columnist Margret Kopala) are
arguing that the relationship between marijuana use and mental illness
is grounds for implementing harsher laws, others maintain it helps
make the case for replacing prohibition with regulation. According to
the Marijuana Policy Project, the largest reform group in the U.S.,
even if the substance were eliminated, schizophrenia would drop to
just three cases per 1,000. Still, that is two cases fewer.

Dr. Robin Murray, a Scottish psychiatrist who began sounding the alarm
about marijuana use and mental illness when he addressed colleagues
from Montreal's Louis Hyppolite Lafontaine hospital at a conference
here two years ago, cited a survey of marijuana users in New Zealand,
that found eight per cent more schizophrenia among them. "If there
were no cannabis in New Zealand, there would be eight per cent less
schizophrenia," he concluded.

As the Conservative government in Ottawa tries to formulate a legal
policy on marijuana use that is consistent, it may want to take into
consideration the health interests of the nation. When a mounting body
of evidence points to the possibility that marijuana is not entirely
harmless - contradicting the prevailing belief in recent decades -
there is reason to conduct a careful and objective assessment.