Second thoughts about marijuana
by Margret Kopala

Published in the Ottawa Citizen, August 27, 2005

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.

MARGRET KOPALA’s column on western perspectives appears every other week.

To comment, please send Margret an e-mail.

Let's make Canada shipshape for the 21st Century