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Note to reader: This is a letter sent to one of the members of the Standing Senate Commitee on Legal and Constitutional Affairs about several of his concerns about cannabis. Copies of the letter (with the accompanying research documents) were also sent to other Committee members.

 June 3, 1996


The Honourable Philippe D. Gigantès
The Senate
Ottawa, Ontario

Dear Senator Gigantès:


At the May 29 hearing of the Standing Senate Committee on Legal and Constitutional Affairs, you stated your concern about two issues -- the level of tar in marijuana, and the supposed increase in potency of marijuana up to 30 times greater than the potency of strains currently available. You also mentioned that the Dutch are planning to lower the limit for the purchase of cannabis in Dutch "coffee shops" from 30 grams to five grams. You suggested that this was because the marijuana was now much more potent.

You then stated:

          I am changing my mind on this until then because of what I have heard about Holland. I feel I cannot maintain my earlier intent to de-criminalize minor marijuana possession of 30 grams or less because possession of 30 grams of this new highly potent marijuana is possession of a very dangerous thing. I would like to know more about this. Until then, I am not prepared to decriminalize or to lower the limits.

I am writing to address these concerns. I hope that the information in this letter will lead you once again to reject the continuing criminalization of cannabis. In short, this letter identifies credible research leading to the following conclusions:

    . that concern over the level of tar in cannabis is largely unnecessary because the vast majority of users consume cannabis only infrequently, and because cannabis can be consumed by means that do not involve inhaling the tar

    . that stories -- often inaccurate -- of increased potency resurface regularly; the purpose of at least some, and perhaps many, of these stories may be to mislead policy makers and discredit attempts to reform drug laws

    . that the supposed "increase" in potency of Dutch cannabis had nothing to do with a decision to reduce the amount available in Dutch coffee shops to 5 grams.

I am enclosing several studies addressing the issues you raised at the May 29 hearing. Aided by these studies, I will deal with each of your points in turn.


1. The level of tar in cannabis

 A joint of cannabis does contain more tar than a cigarette. For example, a person smoking 20 cannabis "joints" would inhale far more tar than a person smoking 20 tobacco cigarettes.

However, an analysis based simply on tar levels is seriously misleading. In 1993, Canadian adult smokers consumed an average of 19 cigarettes per day.See footnote 1 It would be truly extraordinary to find a cannabis smoker who consumed that number of "joints" per day. The pattern of consumption for cannabis tends to be one of much less frequent use, and many fewer "joints" per episode of use. The Le Dain Commission pointed out that even heavy cannabis smokers consume much less marijuana than the average cigarette smoker consumes tobacco leaf, and that fact decreases lung-cancer risk relative to tobacco use.See footnote 2

 A recent New Zealand study on patterns of consumption of cannabis supports the Le Dain conclusion on this point. The New Zealand study found that cannabis consumption was indeed sporadic and moderate in the vast majority of cases. Only one-quarter of those who had used cannabis within the last year used it more than 10 times per month.See footnote 3 One of the most telling statements in this New Zealand study was the following:

        Most people consumed less than one joint per person on a typical occasion.See footnote 4
Compare this with the average Canadian tobacco smoker who consumes 19 cigarettes per day. A major 1989 Canadian study by Health Canada about rates of use of cannabis mirrors the New Zealand study:
        Almost half of all cannabis users (48.6%) reported that they use the substance less than once per month. Another 24.8% use cannabis between one and three times a month, and 22.4% consume the drug once a week or more.See footnote 5
The higher level of tar content is therefore not a significant health issue among the majority of people who use cannabis. Health Canada's own figures conclude that the substantial majority of cannabis users use only infrequently. The amount of tar inhaled will therefore be significantly less than the amount of tar inhaled by a tobacco smoker simply because people who use cannabis use it much less often and in smaller quantities than do people who smoke tobacco.

Perhaps most important, it is not necessary to smoke cannabis; one can ingest cannabis in other ways, thereby completely avoiding the problems of inhaling tar. This is where education about safe modes of ingestion is necessary. Criminalization, on the other hand, does nothing to address the need for safe modes of ingestion.

2. The potency of marijuana

 You stated your concern about the apparent development of a significantly stronger strain of cannabis in The Netherlands. Claims about the "increased" potency of cannabis are hardly new. I am pleased to enclose several studies that deal with alleged increases in potency. All challenge the assertion that the "new" marijuana is more potent and dangerous than the "old" marijuana. Furthermore, even if potency does increase, this does not necessarily increase the harms associated with use. For ease of reference, I reproduce the relevant points from these studies immediately below.

 The first is a 1994 monograph prepared for Australia's National Task Force on Cannabis.See footnote 6 This task force was established in 1992 at the urging of Australian Senator Michael Tate, who was formerly the federal Justice Minister. In part, the monograph states:

         It has been claimed that the existing medical literature on the health effects of cannabis underestimates its adverse effects, because it was based upon research conducted on less potent forms of marijuana than became available in the USA in the past decade. This claim has been repeated and interpreted in an alarmist fashion in the popular media on the assumption that an increase in the THC potency of cannabis necessarily means a substantial increase in the health risks of cannabis use. [my emphasis]

         It is far from established that the average THC potency of cannabis products has substantially increased over recent decades. If potency has increased, it is even less certain that the average health risks of cannabis use have materially changed as a consequence, since users may titrate [adjust] their dose to achieve the desired effects. Even if the users are inefficient in titrating their dose of THC, it is not clear that the probability of all adverse health effects will be thereby increased. [my emphasis]

The second analysis of the potency issue is contained in a 1995 study, Exposing Marijuana Myths: A Review of the Scientific Evidence, by Lynn Zimmer, Associate Professor of Sociology, Queens College (New York) and John P. Morgan, Professor of Pharmacology, City University Medical School.See footnote 7 The authors state:
        The claim that there has been a 10-, 20- or 30-fold increase in marijuana potency since the 1970s is used to discredit previous studies that showed minimal harm caused by the drug and convince users from earlier eras that today's marijuana is much more dangerous.

        THE FACTS

        For more than 20 years the government-funded Potency Monitoring Project (PMP) at the University of Mississippi has been analyzing samples of marijuana submitted by U.S. law enforcement officials. At no time have police seizures reflected the marijuana generally available to users around the country and, in the 1970s, they were over-represented by large-volume low-potency Mexican kilobricks.

        During the 1970s, the PMP regularly reported potency averages of under 1%, with a low of 0.4% in 1974. Quite clearly, these averages under-estimate the THC content of marijuana smoked during this period.

        Marijuana of under 0.5% potency has almost no psychoactivity. While it is possible that people sometimes obtained marijuana of such low potency, for the drug to have become popular in the 1960s and 1970s, most people must have regularly obtained marijuana with higher THC content.

        Until the late 1970s, PMP samples included none of the traditionally higher-potency cannabis products, such as buds and sinsemilla, even though these products were available on the retail market. When changes in police practices resulted in their seizure, PMP potency averages increased.

        Every independent analysis of potency in the 1970s found higher THC averages than the PMP. For example, the 59 samples submitted to PharmChem Laboratories in 1973 averaged 1.62%; only 16 (27%) contained less than 1% THC, more than half were over 2% and about one-fifth were over 4%. In 1975, PharmChem samples ranged from 2 to 5%, with some as high as 14% -- nearly 30 times the .71 average reported by the PMP. (9)

        After 1980, both the number and variety of official seizures increased dramatically, improving the validity of the PMP's reported averages, although they continue to be based on "convenience" rather than "representative" samples.

        . . .          [A]verage potency has remained essentially unchanged since the early 1980s . . ..


        Even if potency had increased slightly since the 1970s, it would not mean that smoking marijuana had become more dangerous. In fact, since the primary health risk of marijuana comes from smoking, higher potency products can be less dangerous because they allow people to achieve the desired effect by inhaling less. [my emphasis]

A 1988 article in the Journal of Psychoactive Drugs also addresses the potency issue:
        The story of new, allegedly stronger and more dangerous marijuana was rebirthed in January 1986 by the late Sidney Cohen, M.D., Professor of Psychiatry at UCLA:

        ". . . material ten or more times potent than the product smoked ten years ago is being used, and the intoxicated state is more intense and lasts longer."

         . . . Despite the respectability of these authorities, none of these alarming claims are new, and neither is the potency issue. [my emphasis]

The article analyses this and many other claims about the increased potency and dangers associated with the "new marijuana". It concludes:


        Observations of the real world of marijuana use, where autotitration is the norm, renders the scare tactics of the new marijuana proponents not only inaccurate but irrelevant. There is much published evidence about the availability of highly potent varieties of cannabis from the nineteenth century through the present day.

        . . .

        In sum, the new marijuana issue is not new and neither is the hyperbole surrounding the issue.See footnote 8

I also draw your attention to the very recent (November 11, 1995) editorial in the internationally respected medical journal, The Lancet. The editorial was written in 1995, when allegedly more potent strains of cannabis were said to be available. Yet the editorial concludes:
         The smoking of cannabis, even long term, is not harmful to health.

        . . .

         Leaving politics aside, where is the harm in decriminalising cannabis? There is none to the health of the consumers, and the criminal fraternity who depend for their succour on prohibition would hate it. But decriminalisation of possession does not go far enough in our view. That has to be accompanied by controls on source, distribution, and advertising, much as happens with tobacco. A system, in fact, remarkably close to the existing one in Dutch coffee shops. [my emphasis]

I also refer you to a British Medical Journal editorial from December 1995, written, like The Lancet article, at a time when allegedly more potent strains of cannabis were said to be available:See footnote 9
        Governments have followed illogical and often counterproductive drug policies, primarily because drug use is seen in moral terms. Wars on drugs are doomed to failure, but experiments with decriminalising and even legalising drugs - as in the Netherlands - have shown promising results. Policies that allow some decriminalisation and legalisation are much more likely than prohibition to succeed in achieving everybody's aim of minimising the harm from drug abuse.
A May 29, 1996, Australian Associated Press report shows further the commitment of some medical communities -- the communities that one would expect to be most strongly opposed to decriminalization if they felt it would be harmful to health -- to decriminalization:
        Medical specialists, lawyers and a Catholic health centre today announced their support for the decriminalisation of marijuana ahead of Friday's parliamentary debate on illicit drugs.

         The Royal Australasian College of Physicians (RACP) and the Law Institute of Victoria today supported decriminalising possession of small amounts of cannabis, as recommended by the Premier's Drug Advisory Council.

        . . .

        President of the RACP, which represents 5,000 medical specialists in Australia and New Zealand, Professor Richard Smallwood, welcomed the council's recommendations as "thoughtful and long overdue".

        He said the RACP also supported the proposed ACT heroin trial, an initiative endorsed by the Advisory Council.

        "As the . . . report points out, an approach to illicit drugs predominantly based on law enforcement is not only highly ineffective but also fraught with problems that can be as damaging as the very problems of drug use," Prof Smallwood said.

Even if the level of potency of cannabis did increase over time, this does not mean that we should therefore continue the destructive policies of criminal prohibition surrounding the drug. It would mean that we should educate citizens about the varying levels of strength of the drug, as we now do with alcohol. It would also mean that we should perhaps regulate its distribution and identify the level of potency of the cannabis (as we now do with alcohol), so that consumers would know the potency of the product they are ingesting.

Remember that alcohol too is available in extremely potent forms. One can purchase 100 per cent drinking alcohol in Ontario liquor stores. Yet the vast majority of people who use alcohol use much milder forms of this "drug". They drink beer or wine or spirits -- despite the availability of more potent forms. Furthermore, if they do drink "harder" liquor, they drink less of it; instead of drinking several glasses of cognac, as one might do with beer, a cognac drinker might consume only a small glass. In other words, drinkers of alcohol adjust the dose to reflect the potency of the particular strain of alcohol they are consuming. Cannabis users generally react in the same manner, choosing less potent forms of the drug, or consuming smaller quantities of more potent forms.

The Canadian Foundation for Drug Policy has never suggested that cannabis is completely harmless. Nor is it necessary that a substance be harmless before it is decriminalized. Almost any substance, from red meat to tobacco to alcohol to calorie-laden desserts, can cause harm if used improperly or excessively. Our position is simply that the policies and criminal laws surrounding cannabis and other drugs almost invariably cause more harm than the drugs themselves.

A final point on the issue of potency: Criminal prohibition almost inevitably leads to pressures to refine drugs into more concentrated forms. This can be seen with heroin (a more concentrated form of opium) and cocaine (a more concentrated form of the active ingredient in coca leaves). Historically, this was also true with alcohol during Prohibition. As American economist Mark Thornton notes:

        Prohibition is clearly the reason for the increase in alcohol potency [in the United States] in the 1920s.

        Not only did producers and consumers switch to higher potency products (from beer to wine to whiskey), they also produced alcoholic products in higher potencies. Beer and wine were often fortified with wood alcohol. Most of the illegal whiskey produced was almost twice the potency as pre-prohibition products.See footnote 10

In short, addressing concerns about potency of drugs requires us to move away from criminal prohibition, instead of embracing it.


3. The proposed reduction in sales of cannabis for personal consumption from 30 grams to 5 grams

At the Committee hearing of May 29, you suggested that the reason for the reduction in the amounts of cannabis that consumers could buy in The Netherlands was the apparent increase in potency of the drug. With respect, the potency of cannabis appears to have nothing to do with the decision to lower the amounts. Instead, it was a political move designed to appease strongly prohibitionist neighbours. As The Lancet stated in November 1995:


        If, as expected, the Dutch parliament agrees the latest proposals, half the country's 4000 cannabis-selling coffee shops will close and the amount that can be sold to an individual will be cut to 5 g. Since the government's own review provides no ammunition for such a change in policy, the real reason behind the new measures must lie elsewhere. One need look no further than the Netherlands' neighbours and co-signatories of the Schengen agreement, which introduced a border-free zone between the Netherlands, France, Germany, Spain, Luxembourg, and Belgium. When France, in particular, threatened to end the agreement, claiming that the Netherlands was the major supplier of Europe's drugs, some action had to be taken and the coffee shops became the scapegoat. [my emphasis]
I also refer you to an April 2, 1996 Reuters news story on this very issue. The article states, in part:
         The Dutch parliament approved government plans on Tuesday for minor changes in drugs policy which essentially preserve the status quo and will allow residents and visitors to continue to smoke cannabis with impunity. The plans stop well short of the clampdown which foreign critics and France in particular had hoped for. Drugs remain illegal in the Netherlands but the authorities will continue to tolerate the sale of cannabis in so-called coffee shops. Parliament has backed plans, however, to cut the amount individual customers may buy to five grams from 30. The move is intended to deter the thousands of young foreigners who flock to the Netherlands to buy drugs which are strictly prohibited at home.

All the evidence I have assembled in this brief analysis points to one conclusion: the continued criminalization of cannabis causes more harm than good. I also remind you of the advice to this effect of many responsible and knowledgeable organizations that appeared before the Committee.

On a more human level, I repeat the question I put to the Committee when our Foundation appeared before it on December 14, 1995:

        I ask members of this committee how they would like their own children to be treated [if they were found to be using drugs]. . . .

        Do you want the police to bust down a door, perhaps with weapons drawn, to handcuff your children, and to take them away and charge them, thus giving them a criminal record? Is that what you want for your children and others you care about? If you do not want that for the people you care about, then how can you want it for the rest of the people in this country? [Yet] that is exactly what we are doing with this law.

        It is easy to speak of how to treat anonymous others, but that is not how we want our own kin to be treated.

I ask for the opportunity to meet with you to discuss this letter further, since the brief analysis of the issues raised in this letter may leave you with further questions.

Yours sincerely,


Eugene Oscapella
Barrister and Solicitor and founding member
Canadian Foundation for Drug Policy

Footnote: 1 Canadian Centre on Substance Abuse/Addiction Research Foundation, Canadian Profile: Alcohol, Tobacco and Other Drugs (1995) at 102. 
Footnote: 2
 This conclusion of the Le Dain Commission was cited in Steven Duke, America's Longest War: Rethinking our Tragic Crusade Against Drugs (Tarcher/Putnam, New York 1993) at 52. 
Footnote: 3 S. Black and S. Casswell, "Drugs in New Zealand: A Survey, 1990" (Auckland: Alcohol and Public Health Research Unit, University of Auckland, 1993). 
Footnote: 4 Ibid. at 17 -19.
Footnote: 5 Health Promotion Directorate, Health Services and Promotion Branch, Health and Welfare Canada, National Alcohol and Other Drugs Survey: Highlights Report (1990) at 12.
Footnote: 6 National Drug Strategy, The health and psychological consequences of cannabis use (Australian Government Publishing Service, Canberra, 1994) at page 17.
Footnote: 7 (New York) (1995).
Footnote: 8 T. Mikuriya, M.D., and M. Aldrich, Ph.D., "Cannabis 1988: Old Drug, New Dangers: The Potency Question", (1988) 20 Journal of Psychoactive Drugs 47 at 47, 53.
Footnote: 9 December 23 - 30, 1995.
Footnote: 10 Mark Thornton, "From Marijuana to Heroin: The Potency of Illegal Drugs", in The Drug Policy Foundation, The Faces of Change (The Drug Policy Foundation, Washington, D.C. 1993) at 7.

Converted by Andrew Scriven


Updated: 24 Jul 2001 | Accessed: 28156 times