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.