Part II

Cannabis: effects, types of use, attitudes

Chapter 5

Cannabis: From Plant to Joint

Cannabis, marijuana, pot, grass, kif, grifa, ganja–from so many cultures, so many names for the drug made from cannabis sativa indica, one of the two main varieties of hemp. Beyond these various names are also different ways in which the drug is used and the context of those various usages: here marijuana is rolled with cigarette tobacco in a cigarette paper (joint), there kif is smoked in a pipe and elsewhere ganja is smoked in a water pipe. Sometimes it is baked into cookies or cakes. The French pétard, the English joint or the Indian bangh are all names for the product consumed and, at the same time designate different usages: marijuana is most often composed of the plant's flowering tops and dried, powdered leaves; sinsemilla is a preparation consisting of female tops of a private variety of seeds, whereas Indian ganja consists solely of fertilized flowering tops.[1]

These names are not mere accidents of folklore: like other substances, cannabis has codified uses that vary across cultures. The words used to name the same drug refer to a set of relations that populations of various cultures maintain with it, a kind of code of manners, but also of reasons to use the drug. In North America (United States and Canada), marijuana has long been identified with youth and the sexual liberation of the 1960s; in India and Jamaica, ganja has religious aspects which it does not necessarily possess in the West; and this same drug has still other cultural meanings in the Maghreb. We return to this question in Chapter 6.

This chapter first describes the cannabis plant and the various forms in which it becomes a consumer drug. We then take a brief look at the geographical origin of the cannabis plant and the routes along which it circulates in the modern world, noting at the same time its current modes of production (soil‑based and hydroponic) which have developed in certain regions of Canada. We then describe the pharmacokinetics of the cannabis plant, in particular its main active ingredients and their metabolism in the body.


One plant, various drugs[2]


There are a number of varieties of cannabis. The best known are Cannabis sativa, Cannabis indica and Cannabis ruderalis. Cannabis sativa is the main variety which grows in virtually any climate. In dry, sandy and slightly alkaline soils, it yields plants that can reach up to seven meters in height. In Canada, the preferred variety for soil‑based cultivation is Cannabis indica, which is a shorter plant, but with higher concentrations of D9‑THC (the main active ingredient of cannabis, discussed more fully below). There are male and female plants. In general, female plants are richer in D9‑THC than the males, which are often smaller and bare of leaves. D9‑THC is mainly found in the resin secreted by the flowering tops.



Flowering tops and leaves of cannabis



It appears that cannabis was first known in China some 6,000 years ago, then subsequently in India, then the Middle East, Africa, Mexico and South America. Cannabis can be cultivated in a number of ways, in greenhouses or hydroponically, which makes it possible to increase plant productivity and achieve high D9‑THC levels. Methods for genetically selecting the best greenhouse varieties and crops have also made it possible to increase the active ingredient content.

Male and female cannabis plants


Marijuana, which is a Mexican term initially used in reference to cheap tobacco, but which subsequently designated certain parts of the cannabis plant, is generally green or brown in colour and produces a characteristic odour when burned. It resembles oregano or coarse tea.[3] Marijuana comes from all the parts of the plant once dried. In this form, its THC content is lower; THC content is increased by selecting the flowering tops of the female plant. Dried and coarsely powdered, marijuana is most often rolled into thin cigarettes together with cigarette tobacco (joint), and sometimes smoked in a pipe or, less frequently, in cigar form. A typical joint contains between 0.5 and 1 g of cannabis. Like hash, it can also be baked into cookies and cakes, and be drunk as an herbal tea as well. A number of specialists told us that domestic cannabis made through controlled greenhouse production costs approximately $100 an ounce, and is then sold on the street at average prices ranging between $200 and $250. While we consider this estimated production cost high, the only other available studies concern production costs in developing countries such as Morocco.



Marijuana and joints

Hashish, also known as hash, shit, kif (in North Africa) and charas (in India), is the viscous resin produced by the marijuana plant and obtained by pounding then compressing the dried leaves and flowering tops to obtain what, in France, is called a "barrette" or here a cube or block. It takes approximately 45 to 75 kg of cannabis to produce 1 kg of hash, which is sold in light brown to black pieces of hard or soft consistency. It is frequently smoked, alone or mixed with tobacco or marijuana, in a cigarette (joint), pipe or, more rarely, cigar. It may also be baked into cookies or cakes. The D9‑THC content of hash is generally between 3% and 6% in normal production. As is the case for cannabis, D9‑THC content can be increased through growing methods and resin concentrations to achieve levels of more than 10% on average. Slightly more expensive than marijuana, hashish sells for approximately $300 to $350 an ounce on the street.




There are two other cannabis‑based products, marijuana and hashish oils, which are extracted from resin using 90‑proof alcohol, which is subsequently evaporated through exposure to the sun. These oils are viscous, greenish brown to blackish, foul‑smelling liquids, with generally higher cannabinoid concentrations of up to 30% to 60% D9‑THC. Oils are generally dripped onto cigarette paper or tobacco then smoked. They are scarce and more expensive than other products.




Cannabis oils


The following passage from a report prepared by Labrousse and Romero for the Observatoire français des drogues et des toxicomanies (OFDT; French Monitoring Centre for Drugs and Drug Addictions) in 2001 on cannabis production in Morocco describes the various stages of production very clearly.

Text Box: From Cannabis to Oil – The Production Process in Morocco
Kif is the name given to the cannabis plant as a whole. (…) Cut and dried in the sun (generally on rooftops) for at least a month and a half, it is preserved in houses for several months under plastic tarpaulins. Chopped by hand with a special knife on a board, it is then mixed with tobacco for smoking. The traditional mixture consists of one﷓third kif, two﷓thirds tobacco and is smoked in a sebsi, a long wooden pipe with a terracotta or stone pipe bowl.
Chira is the powder resulting from solidification of the small resin drops exuded by the flowering tops of the female plants. To separate the resin from the dried plants, processors pound or shake the plants over a stretched thin nylon veil that serves as a screen. The first powder to fall, golden beige in colour, is called sigirma. This is the top quality, so﷓called double﷓zero powder which is said to contain as much as 20% THC. The next powder to fall is called hamda, which is mixed with plant waste giving it a greenish colour. Hamda is lightly screened to yield various product qualities: zero, no. 1, no. 2, no. 3 and no. 4 (the lowest quality), containing respectively from 10% to 2% THC. (…) It takes approximately 100 kg of kif to obtain 1 kg of top﷓quality hashish.
Peasants (…) told us that the rest of the operation, when carried out by traffickers, took place in ostensibly secret buildings isolated in the mountains. (…) There the powder is placed in cellophane bags, then heated and compressed to yield resin or hashish, readied for the market in the form of small bars (generally 250 grams) called tbisla or "little plate". (…) The "double zero" quality, which derives its name from the two holes made in the bar with the end of a lit cigarette, is reserved for domestic consumption and preferred customers. Misinformed foreign customers often receive hash that has been cut with black polish, glue, henna, fig, earth or even medication.
(…) Cannabis oil is derived from no. 3 and no. 4 quality resins and produced by diluting hashish in a container with pharmaceutical alcohol. After six to eight hours of distillation, the liquid is filtered and stirred until all the alcohol has evaporated. Local production of this high value﷓added liquid (it takes 10 kg of hashish to produce one liter of oil) is less marginal than is generally thought.

Labrousse, A. and L. Romero (2001) Rapport sur la situation du cannabis dans le RIF marocain. Paris: OFDT.



Cannabis roads


Where does the cannabis and hashish available in Canada come from? What quantities are imported and how much is produced locally? What routes are used to transport the drugs between provinces? What quantities are exported to other countries? What is the monetary value of this market? These are constantly recurring questions. They serve various purposes: to underline the scope of the drug “problem” generally, to explain the power of organized crime which makes money from drugs, as well as to substantiate the discrepancy between the size of the problem and the limited resources governments allocated to reducing supply. But this information can also assist in better understanding the extent of the problem experienced by peasants in the various producer countries, the ecological issues raised by the cultivation of drugs, as well as the strategic position of drugs in geopolitics.

The cultivation of cannabis is the most widespread of all illegal drugs, which is not surprising since, not only does the plant grow readily in a number of climates, but it also requires little processing before becoming marijuana. According to the 2000 report of the United Nations Drug Control Program (UNDCP):


Over the last decade, 120 countries reported illicit cultivation of cannabis in their territory. Interpol identifies 67 source countries for cannabis through seizures made in 1998. (…) Estimating the extent of illicit cannabis cultivation, production and trafficking is much more difficult than for other plant‑based drugs because of the significant amount of wild cannabis growth, the diverse nature of cultivation and the sheer magnitude of trafficking. In contrast to other plant‑based narcotic drugs, illicit cannabis products can originate from three qualitatively distinct sources of supply: outdoor illicit cultivation; naturalized cannabis plant populations (wild growing cannabis); and plants cultivated indoors by means of sophisticated growing technology. (…) The large number of countries reporting an increase in cannabis consumption (two‑thirds of all countries reporting drug abuse trends in 1996) would suggest that overall production must have increased; but this is only partly confirmed by seizure data. (…) Cultivation estimated (including wild growth), based on reports from Member States in the 1990s, ranges from 670,000 hectares to 1,850,000 hectares. Production estimates vary by a factor of 30, from 10,000 tonnes to 300,000 tonnes. Linking production and consumption estimates, UNDCP estimates world wide cannabis production to be at about 30,000 tonnes. [4]


Text Box: Variable Estimates – The Case of Morocco
In their study, Labrousse and Romero state that, according to the Department of Agriculture, cannabis was produced on 75,000 hectares in 2000. (By comparison, in its 2000 report, the ODCCP cites the figure of 50,000 hectares in cannabis production in Morocco, an official figure provided by the Department of the Interior.)
Based on their own work in the field, they estimate that 90,000 hectares were in production in 1999 and between 110,000 and 120,000 in 2001. That production involved approximately 200,000 families, between one and one and a half million persons. Based on those areas, production would be between 1,600 and 3,000 tonnes, after deducting the quantities of kif set aside for national consumption.
Labrousse and Romero, op. cit.
As may be seen, estimates vary greatly and are enormously difficult to validate. How can anyone estimate the number of cannabis plants that are transformed into marijuana? The data provided by the governments of various countries on cultivated areas are themselves only approximations. As to the number of greenhouses and other forms of production, there is quite literally no way of knowing.

The work of the team at France's Observatoire géopolitique des drogues, under the direction of Alain Labrousse, is exemplary in the field. The box from the same report produced for the OFDT in 2001, describes a three‑month field project in which the authors cross‑checked data from various sources.


In particular, it has been observed that, when linked to the population of potential cannabis users (which the Centre estimates at some 120 million persons), the estimated global production of 30,000 tonnes is much nearer the 10,000 tonne floor than the 300,000 tonne ceiling.

According to the UNDCP, the main producers are Colombia and Mexico (marijuana) and Morocco (hashish). According to the International Criminal Police Organization (Interpol), Morocco, Afghanistan and Pakistan are the main sources of hashish and Colombia, Niger and South Africa of cannabis. Lastly, according to Labrousse, marijuana production is exploding, with Colombia becoming again the major producer it was in the 1970s, and production rapidly increasing in West Africa (Nigeria, Ghana, Congo, Ivory Coat, Senegal), although the great steppes of the Commonwealth of Independent States (Kazakhstan, Kirghizistan, Ukraine, Belarus and Azerbaijan) have virtually unlimited export potential, while Afghanistan and Pakistan likely produce 2,000 tonnes of hashish, the equivalent of Morocco's production.[5] In addition, Canada has been a cannabis exporting country for a number of years now.[6]

Traditionally, the cannabis available in Canada comes mainly from Mexico, Jamaica and the countries of the horn of Africa, while hashish originates mainly in Asia and the Middle East:


The hashish market in Central Eastern Canada is known world‑wide. U.S. criminals are among the international traffickers who orchestrate multi‑tonne shipments of this drug from Pakistan directly to Montreal by mothership or container. In 2001, some shipments transited the United Arab Emirates, Africa and Europe before reaching Canada. Multi‑kilo quantities are also imported from Jamaica by couriers travelling on board commercial airlines. [7]


While a large portion of cannabis sold in the Canadian market was of foreign origin until the 1980s, the situation has radically changed since that time. It is estimated that national production has now supplanted imports. In its 1999 report, the Royal Canadian Mounted Police writes:


It is estimated that more than 50% of the marihuana available in Canada is produced domestically. Of the foreign marihuana seized in or en route to Canada in 1999, at least 5,535 kilograms originated from Jamaica, 825 kilograms from South Africa and 860 kilograms from Mexico. Foreign shipments arrive directly into Canadian ports of entry or transit through the United States before reaching Canada. On June 11, 1999, U.S. Customs intercepted 2,464 kg of Jamaican marihuana and 141 kg of hash oil at Newark, New Jersey in a marine container bound for Montreal. Furthermore in Project JOULE on June 20, 1999, 2,617 kg of Jamaican marihuana destined for Canada were seized in Stuart, Florida. [8]


How much cannabis and hashish are available in Canada? What is the monetary value of those drugs? It is in fact impossible to answer these questions, for obvious reasons, since the drugs are illegal. While we know the amount of tobacco produced and sold in cigarette form, and the volume of alcohol produced or imported and consumed, and sales turnover can be calculated in both cases on the basis of those volumes, it is impossible to do this for illegal drugs.

For a time, the United Nations International Drug Control Program suggested that the total value of the illegal drug "industry" was approximately US $400 billion, greater than the oil industry.[9] The total value of cannabis obviously cannot be separated from that amount, even though we know that the largest number of persons who use drugs use cannabis. No one really knows how or on what basis these figures are advanced, whether they were produced using a rigorous calculation method or merely noted down on a napkin over a meal.[10] And yet they often serve as a reference. In a series of articles published on the illicit drug issue in 2001, The Economist cited the $400 billion amount before suggesting a more conservative estimate of US $150 billion.[11] By comparison, the value of the pharmaceutical industry is near US $300 billion, that of the tobacco industry $204 billion and that of the alcoholic beverages industry $250 billion.

Since the authors provide itemized accounts of their calculation methods, we will now continue our analysis of the Moroccan example.


Text Box: Yields and Returns from Cannabis – The Case of Morocco
Cannabis is a not very demanding plant that grows in poor soils, which it quite quickly renders unfit for any other form of agriculture. As a result of the illegal nature of this crop, the income it generates is disproportionately high compared to that from legal food and cash crops. It is also a non﷓perishable product that can be sold from the home, into an ever certain market and on credit. In particular, it enables local populations to improve their living conditions and opens the way to initiatives by the peasants themselves.
Estimates of per﷓hectare cannabis income vary with soil type, rainfall, degree of irrigation, whether the cannabis is processed into chira (powder), period of sale and other factors. In addition, researchers give various estimates based on the same criteria. This is due to the fact that it is difficult to obtain reliable data from mistrustful peasant farmers. Income from the production of unprocessed kif varies, depending on sources, from 12,450 to 210,000 French francs per hectare.
(…) while cannabis is highly profitable on irrigated perimeters, it is much less so on pluvial lands, particularly in poor years. (…) Many peasant farmers who likely cultivate only 1.5 ha to 3 ha (non irrigated) of cannabis, earn, in poor years, only 20,000 F to 40,000 F from that crop to support families of, in many cases, more than 10 persons.
(But) cannabis is 12 to 46 times more profitable than grain crops.
In 1997, based on production of 1,397 tonnes of hashish for the Rif as a whole, Pascual Moreno estimated the return for Moroccan producers (from the peasant farmer to the major trafficker) at $1.816 billion. Since a certain number of Moroccan traffickers operate outside the country, Moreno estimated the return to the Moroccan economy from cannabis profits at $2 billion, compared to $750 million for textile exports, $460 million from foreign investments and $1.26 billion for tourism. He also estimated the profits of European traffickers at $3 billion (apparently not including street sales).
However, since cannabis is more profitable than any other crop, peasant farmers tend to abandon food crops and to supply themselves from the market. As a result, there is a growing food shortage in the region.
Labrousse and Romero (2001) op. cit.: 12﷓15.


We know of no similar field work for Canada or Mexico. In addition, in Canada, climatic conditions have stimulated development of greenhouse and hydroponic crops, and the ratio of these cultivation methods to soil cultivation methods is not known.

We therefore use the following figures and data on cannabis production, cannabis and hashish imports and the monetary value of those drugs in the Canadian market, with considerable reservation and prudence.

According to the RCMP, "the annual production of marijuana in Canada [is] at least in the 800 tonne range. This estimate appears overwhelming, however investigators believe it is quite conservative, and it is supported by intelligence and seizures of marijuana in plant and bulk forms."[12] The same figures are stated in the 1998 and 2002 reports. Note as well that, at 800 tonnes, Canadian production represents approximately 2.5% of global production, as stated by the UNDCP.

In its 1998‑1999 annual report, the Observatoire géopolitique des drogues stated that, based on police sources, the value of the illegal drug market in Canada was $7 billion to $10 billion a year.[13] For 2001, the RCMP estimated that the market value of all illegal drugs was $18 billion.[14] It is impossible to estimate the share of cannabis and hashish in that total. As we most often do not know the calculation basis for these estimates, they must also be prudently considered. As the Assistant Deputy Solicitor General stated in his appearance before the Committee, the calculation methods, based on the assumption that police and customs organizations seize 10% of all drugs, are unscientific and unreliable.[15] We nevertheless note an apparent inconsistency: the seeming stagnation of cannabis production at 800 tonnes and of hashish imports at 100 tonnes since 1998, as well as the declining prices of heroin and cocaine in a stable, even declining market (RCMP reports) are not consistent with the presumed doubling in total value of the drug market. As a result, in dealing with these various estimates of the quantity of drugs produced and monetary value of the drug market, the Committee often had the impression that, ultimately, no one really knew how big it was.

With regard to hashish, the RCMP believes that it


is easier to estimate the quantity of hashish entering the Canadian market annually than the quantity of any other illegal drug. Unlike what is observed for other drugs, such as cocaine and marijuana, that can be found across Canada and the United States, hashish use in North America is a localized phenomenon. The drug is very popular in Quebec, Ontario and the Atlantic Provinces, whereas demand is limited elsewhere in Canada and supply is sporadic at best in the northeastern United States. Consequently, Montreal organized criminal groups are specialized in the massive importing of hashish and have a monopoly on its distribution in bulk. In view of these facts and of information on multi‑tonne hashish shipments seized in Canada and abroad and on those we know have entered the Canadian market, RCMP analysts estimate that at least 100 tonnes of the drug are imported into Canada each year. [16]


Canada is also an in-transit country for drugs to the United States, and a significant portion of Canadian cannabis is intended for export, in particular to that country.


Smuggling of Canadian marihuana to the United States remains a source of concern for enforcement officials on both sides of the border. Though this activity is particularly noticeable on the British Columbia–U.S. border, it is not limited to that province. There is intelligence that the Hell's Angels in Quebec are supplying marihuana to their U.S. counterparts. Intelligence also indicates that there is marihuana smuggling activity across the Great Lakes. Despite the foregoing, few U.S. marihuana seizures can be traced back to Canada. [17]


In 1999, Washington officials suggested that Canada could be placed on the list of countries suspected of a soft stance in the fight against drug production and trafficking. More recently, officials of the Drug Enforcement Administration repeated that Canada's trafficking in cannabis toward the United States was a significant problem. One RCMP officer told a national newspaper that approximately 70% of marijuana grown in Canada wound up in the United States,[18] whereas, according to the 2002 report of the International Drug Control Agency, the figure was approximately 60%.[19] We have heard, and RCMP officers confirmed it, that cannabis from British Columbia has such a high value that it was traded on par with cocaine. According to those police officers specialized in the war on drugs, British Columbia's triple A quality cannabis is worth approximately $4,000 a pound in Canada and one kilogram of cocaine is currently worth US $11,000. However, while reference is made to this supposition in the annual report for 1999, it is not confirmed:


Canadian marihuana is sometimes used as a currency to purchase cocaine that is warehoused in the U.S.A. The exchange ratio is about three to one. Exchanges of one to one have been rumoured but never substantiated. Furthermore, such a rate of exchange does not make sound commercial sense considering that a kilo of cocaine sells for $13,000 U.S. (in lots of 50 kilos or more) while the wholesale price of a kilo of marihuana ranges around $6,000 or $8,000 U.S. [20]


In its 2002 report, the RCMP merely mentions the fact that Canadian cannabis is exchanged for cocaine, without saying whether it is on an equal weights basis. We also note a certain inconsistency here as the price of a kilogram of cocaine is expressed in US dollars, whereas that of a kilogram of marijuana is expressed sometimes in Canadian dollars, at other times in US dollars.

British Columbia, Ontario and Quebec are the main producers in Canada. British Columbia's large production can be attributed in particular to suitable climatic conditions, but there are probably also sociocultural explanations, as the Pacific Coast mentality explains in part why cannabis appears to have taken root there to a greater extent.

Cannabis production in British Columbia appears to have increased significantly over the past 10 years, becoming, according to some analysts, one of the province's biggest industries in terms of monetary value, which some analysts set at $6 billion, whereas, according to some police officers, a conservative estimate would be $4 billion.[21] If marijuana sells for $225 an ounce, at 16 ounces a pound, British Columbia would appear to produce the equivalent of 550 tonnes of cannabis a year, more than two‑thirds of the total amount of cannabis circulating in Canada.

Testifying in Richmond, B.C., on 14 May 2002, RCMP Superintendent Clapham said there were between 15,000 and 20,000 illegal cannabis production sites in British Columbia (figures from the Drug Enforcement Administration), while RCMP narcotics specialists, the next day, put the figure at 7,000. Regardless of the true number, the figures, as may be seen, must necessarily be considered very carefully.

As to growing methods, soil‑based production is still the most popular, but the more sophisticated, hydroponic and aeroponic,[22] methods are expanding, particularly among criminal gangs that have the necessary infrastructure.


It is not uncommon to find indoor grow operations involving over 3,000 plants. Those figures vary considerably from one province to another, overall less than 10 percent of all marihuana seized in Canada was grown using hydroponics (a method of growing plants with the roots in nutrient mineral solutions rather than in soil). Indoor grow operations still rely mostly on soil‑based organic cultivation but hydroponics is gaining in popularity. Despite the availability of highly sophisticated technologies designed to increase the yield even more, most growers do not bother to go to such lengths, preferring simpler and proven methods. Marihuana remains the most popular illicit drug, both in terms of consumption and trafficking. The annual marihuana production has been estimated to be around five million plants. Given the relatively low cost of setting up a grow operation and the considerable profits it generates, this activity has become increasingly attractive, even to otherwise law‑abiding citizens. In the majority of regions, large operations are invariably run by outlaw motorcycle gangs, although Asian‑based organizations have been making inroads in British Columbia and Alberta. More and more groups are using "crop sitters" and other go‑betweens to tend their plantations. This hands‑off approach makes it difficult for police to link the operation to the people who are actually behind it. Outdoor crops are often grown on Crown lands located in remote areas in order to reduce the risk of detection. [23]


In all, with considerable reservations as to the validity of the data, the Committee submits the following:





Estimated quantity

‑ national production

800 tonnes

approximately 50%

100 tonnes






National production (British Columbia, Ontario, Quebec)

Imports: Mexico, Jamaica


Imports: Pakistan, Afghanistan, Morocco


Value (wholesale)


$2,000 to $4,000/pound



Retail value (ounce)

$225 to $250

$325 to $350


Properties of cannabis


Classified in the pharmacopoeia as a hallucinogenic, psychodysleptic or psychotomimetic, cannabis is a disrupter or modulator, that is to say that it alters perceptions and emotions. Classified in the international conventions and national legislation as a narcotic, cannabis belongs to the class of psychotropics which comprises five major groups: depressants (alcohol, Valium), stimulants, minor (coffee, nicotine) and major (cocaine, amphetamines), disrupters (cannabis, LSD), antipsychotics and medication for mood disorders (lithium).

More than 460 known chemical constituents are present in cannabis.[24] Of that number, more than 60 are identified as cannabinoids. The main active ingredient in cannabis, which was identified by the team of Dr. Mechoulam in 1964,[25] is D9‑tetrahydrocannabinol, common called THC. Other cannabinoids present in Indian hemp include delta‑8‑tetrahydrocannabinol, cannabinol and cannabidiol, but they are present in small quantities and have no significant effect on behaviour, compared to D9‑THC,[26] although they can modulate the product's overall effect.[27] Cannabinol also has anti‑inflammatory effects.

For a better understanding of the effects of cannabis discussed in the following chapters, we will first consider its pharmacological properties. Consequently, readers may skip this technical section without risk of not properly understanding the rest of the report. In the following paragraphs, we first discuss D9THC levels and, second, specifically examine the pharmacological properties of that substance.


D9THC Concentrations

The D9THC content of marijuana generally varies in natural growing conditions from 0.5 to 4%.[28] D9THC content serves first as a basis for distinguishing the drug type of plant from the fibre type: permitted concentrations vary by country - in Canada, as in France, it is 0.3% for the fibre type. For more than a decade now, techniques for selecting powerful strains and cultivation (in greenhouses and hydroponically) have made it possible to achieve D9THC concentrations of 15% or more. D9THC content is also used to distinguish between various cannabis products and thus to determine their price: the content of sinsemilla, for example, generally varies between 7% and 14% and is more expensive than "regular" cannabis.

The question of D9THC content, its variability, how it is determined and its effects has raised numerous issues. While all specialists agree that maximum active ingredient concentrations have increased over the past 20 years, opinion is divided on average concentrations in cannabis available on the market. Estimates vary as to the preponderance and consequences of D9THC concentrations.

First, it should be emphasized that studies show that concentrations are subject to extreme variability, for a number of reasons. First, failing a control system at source, the D9THC content of marijuana is estimated on the basis of police seizures. However, only a portion of the drug seized is analyzed for THC content,[29] and analyses are not all equally reliable, depending on how police or customs officials conducted the seizures and how the products were preserved and transported to the lab. In addition, between a seized product in clandestine lab or at a customs post and the product sold on the street, a number of changes can be made: tobacco, herbs and other products can be added to the gram of "pot" sold at a school which alter the nature of the drug and thus the quantity of active ingredient. This is even truer for hashish, as seen above in the example on processing in Morocco.

Second, since cannabis is a widespread illegal product, it is impossible to take a representative sample of the drug available on the market at a given time for analysis. Thus it is impossible to measure the difference between the D9THC content of cannabis seized at the production or delivery site and that of cannabis used by individuals. And third, the active ingredient concentration varies with the geographical area of origin, climatic conditions and production conditions. Likely circulating in the market at any given time is a significant variety of cannabis products reflecting the diverse conditions in which they were produced. It follows that two samples seized in Vancouver in the same week could have very different concentrations, as would be the case for samples seized the same week in Vancouver, Montreal and St. John's.

Experts told the Committee that cannabis in the Canadian market was 700% more powerful than the same drug in the 1970s. Some suggested that the average D9THC content of cannabis on the market is approximately 30%, compared to 3% to 4% in the 1970s.


The cannabis used today is up to 500 percent higher in THC - that is a range between five percent to 31 percent - than the cannabis most adults remember from the 1960s and 1970s. [30]


In its 1999 annual report, the Royal Canadian Mounted Police estimated the average content of seizures at 6%.[31] In Quebec, the Montreal Police Department asserted that the THC content of cannabis is now 25%. In a private meeting with Committee members, RCMP narcotics experts in British Columbia emphasized that it is impossible in the current state of affairs to determine the average content of cannabis in the country or in a given province, in particular as a result of the extreme variability of seizures and methods of analysis. The officers who conduct the seizures do not always pay attention to the manner in which they preserve the product, such that it may lose its D9THC content: heat, light and humidity affect the stability of cannabis. Lastly, the experts providing cannabis for therapeutic purposes whom we met said they kept various grades of cannabis, based in particular on D9THC concentrations, and that, in certain cases, the products offered to patients reached concentrations of 27%.

The most exhaustive studies on changes in D9THC levels in cannabis have been conducted in Australia, the Netherlands, France and the United States. They show, first, that more powerful products have appeared in the market beside the traditional forms of cannabis: "skunk" (a variety originating in the United States and the Netherlands), "super‑skunk" and "pollen" (stamens of male plants). Canada has not lagged behind, with BC Bud and Quebec Gold in particular.

More specifically, the studies on D9THC concentrations show similar trends:

·               In Australia, a study by Wayne and Wendy on 31,000 seizures conducted between 1980 and 1997 shows that average content varied little over the period and was between 0,6 % and 13 %. Among other things, it appears that the main development has been a more significant selection than previously of the parts of the plant with the highest concentrations.[32] The authors of this study make the following observation which applies equally to Canada:


A number of factors probably explain the persistence of the belief that the THC content of cannabis plants in Australia has increased 30 fold in the absence of any supporting data. First, defenders of the claim often point to reports of single samples with unusually high THC content tested by the police. At best, such samples indicate the maximum THC content that has been achieved (assuming that there were no errors in the test results) but they do not tell us what the THC content is in the cannabis that is typically used by consumers. Second, biases in the sampling of tested cannabis are amplified by the attention that the print and electronic media give to unusually potent samples, creating the false impression that cannabis with exceptionally high THC is the norm. Third, uncontested repetition of these assertions in the media has established them as “fats”; those who context these claims are asked to prove that they are false rather than the (usually nameless) proponents being asked to provide evidence that they are true. Fourth, an increase in average THC content seems to explain an apparent increase in the number of cannabis users who experience problems as a consequence of their use. [33]


·               In the Netherlands, the Drug Information Monitoring System of the Trimbos Institute has conducted various studies since 2000 on average D9THC content. The local variety, Nether‑Weed, contained an average of 8.6% THC in 2000 and 11.3% in 2001, whereas imported varieties were stable at approximately 5%. One of the reasons given for this difference was that the local variety was fresher and contained a lower ratio of cannabinol to D9THC. In addition, Nether‑Weed resembles sinsemilla, which comes from the unfertilized flowers of the female plant and is cultivated in greenhouses.

·               In France, the Roques report referred to concentrations of up to 20% in the case of certain Dutch hydroponic varieties.[34] In its recent report, France's Institut national de la santé et de la recherche médicale notes a toxicological study conducted by Mura on the D9THC concentrations of seizures since 1993. From 1993 to 1995, the average concentration was 5.5%, but approximately 8% since 1996, with spikes of up to 22%.[35] In 2000, 3% of marijuana samples analyzed contained D9THC levels of more than 15%.

·               Lastly, in the United States, data for 2000 show an average concentration of 6%, compared to 4.1% in 1997. In fact, recalling a study recently conducted in Mississippi, Dr. John Morgan noted:


(…) in the midst of this furore over the remarkable increases in marijuana potency, it is interesting that the potency of the commercial crop sold in the United States has not varied enormously over the 30 years that potency has been assessed by the analysis of THC content in criminally seized marijuana. In fact, I recently looked at the report, which also comes from Mississippi, that the mean THC content of some 40,000 seizures since 1974 is about three percent. It has gone up in the last 10 years. In fact, in the last 10 years I believe the arithmetic mean is more than four percent while in the 10 years before that it was about 3.5 percent. [36]


The following table summarizes some of the data on a historical basis for certain countries.


Year analysed

Domestic Marijuana (USA)

Foreign Marijuana (Netherlands)


Sinsemilla (USA)

Nether-Weed (Netherlands)


≥ 3 %            ≥ 5 %           ≥ 9 %

≥ 3 %            ≥ 5 %             ≥ 9 %

USA, 19961

63%                25%              3%

93%                 77%                49%

USA, 19971

63%                29%              6%

96%                 85%                64%

USA, 20002

Average of 6.07% (DEA)

Average of 13,65% (DEA)

Netherlands, 2000-20011

75%                48%               7%

93%                 87%                35%

Netherlands, 2001-20021

80%                55%               4%

100%               99%                78%

Australia, 19973

Between 0.6% and 13%


Western Australia

Average of 3,8%


Canada 19994

Average of 6%

Not available

(1)     Source: Rigter H. and M. von Laar (2002) " Epidemiological Aspects of Cannabis Use", International Scientific Conference on Cannabis, Brussels, page 32.

(2)     Drug Enforcement Administration,

(3)     Source: Hall, W. and W. Swift (2000) op. cit., page 505

(4)     Source: RCMP, Annual Report for 1999.



In short, it appears that the main change has been in maximum concentrations obtained as a result of sophisticated cross‑breeding and cultivation methods, whereas average concentrations have not significantly changed over the past 30 years.[37] What conclusion can be drawn from this? In the minds of some, if cannabis could still be called a "soft drug" in the 1970s, that is no longer the case today. Some are not reluctant to say it is a drug comparable to heroin or cocaine in its addictive power. As an example, the Canadian Police Association has issued the following opinion on the risks associated with cannabis.


Generally, marijuana and its derivative products are described [as soft drugs] to distance the drug from the recognized harm associated with other illegal drugs. This has been a successful yet dangerous approach and contributes to the misinformation, misunderstanding and increasing tolerance associated with marijuana use. Marijuana is a powerful drug with a variety of effects. (…) Marijuana use is associated with poor work and school performance and learning problems for younger users. Marijuana is internationally recognized as a gateway drug for other drug use. Risk factors for marijuana dependence are similar to those of other forms of drug abuse. [38]


Others associated the increase in demand for treatment for cannabis dependence with the increase in active ingredient concentrations. As the National Post reported:


The potent BC Bud, which has a THC content as high as 25% compared to the 2% typical in the 1970s, is also leading to health concerns in the United States. Admissions for marijuana drug treatment in Washington State now exceed the rate for treatment of alcoholism. Cannabis admissions in Cook County, Ill., have risen by 400% in the last year. [39]


Can it be said that cannabis has in fact become a "hard" drug like cocaine and heroin? Apart from the validity of the effects of cannabis itself as described by the Police Association, and as will be discussed in detail in the Chapter 7, that contention does not take into account the way in which the drug is used or the lack of knowledge of the effects of D9THC concentrations. Studies on the ways in which cannabis is used, considered in Chapter 6, show that regular users appear to prefer medium to mild cannabis, and that they adjust their use to the strength of the drug. Interviews with individuals who use cannabis for medical purposes tend moreover to confirm this perception. More significantly, for lack of any specific studies on the question, the effects of higher D9THC concentrations are simply not known. Lastly, as will be shown in the following section, the bio‑availability of D9THC, that is to say the proportion that is actually absorbed by the body following combustion, is highly variable. As emphasized in the report of the World Health Organization (WHO) on cannabis, considering all these factors, the actual quantity of THC absorbed by the cannabis user is difficult to estimate.[40] Ultimately, while it can be a legitimate preoccupation, the real issue of D9THC content has more to do with our ability to control it and better know its effects, rather than making all kinds of alarmist and unfounded statements about its level.


Pharmacokinetics [41]

Upon inhalation, and depending on the smoker's way of smoking and smoking experience, between 15% and 50% of the D9THC present in the smoke is absorbed into the bloodstream. The percentage also depends on the D9THC concentration in the smoked product. The substance is absorbed very quickly, and maximum blood concentrations are achieved in less than 15 minutes after the start of inhalation. The effects felt almost immediately after absorbing the smoke diminish gradually over the next 60 minutes and generally last a maximum of three hours after inhalation. In other words, THC levels in the blood plasma are highest immediately after absorption, whereas maximum effects are felt approximately 30 to 40 minutes later. The following table reproduced from the ISERM collective assessment, shows the time to appearance and duration of detection of cannabinoids in the blood.[42]



Concentration, time to appearance1 and duration of detection2 of cannabinoids in the blood after smoking a marijuana cigarette containing 15.8 mg or 33.8 mg of D9THC


Maximum concentration

Time to appearance

of peak (hr)

Duration of detection



84.3 (50‑129)3

162.2 (76‑267)4


0.14 (0.10‑0.17)

0.14 (0.08‑0.17)


7.3 (3‑12)

12.5 (6‑27)


6.7 (3.3‑10.4)

7.5 (3.8‑16.0)


0.25 (0.15‑0.38)

0.20 (0.15‑0.25)

4.5 (0.54‑12)

11.2 (2.2‑27)


24.5 (15‑54)

54.0 (22‑101)

2.43 (0.8‑4.0)

1.35 (0.54‑2.21)

84.0 (48‑168)

152.0 (72‑168)

(1)     average interval between start of consumption and appearance of a concentration peak

(2)     average interval between start of consumption and moment when lowest concentration of component is detected (> 0.5 mg/ml)

(3)     cigarette containing 13.8 mg (1.75%) of D9THC

(4)     cigarette containing 33.8 mg (3.55%) of D9THC


Bio‑availability of D9THC is slower and weaker when the drug is ingested orally (cookies, cakes, herbal teas): approximately 4% to 12%; although slower to be felt and different in quality, its effects are longer lasting.

In all, we do not know how the effects of THC (concentration) interact with personal factors (way of smoking, health status, alcoholism or medication). However, it is likely that the same THC concentration does not have the same effect on all smokers, which moreover tend to be confirmed by the plasticity of cannabis in the hormonal stream (see below).

D9THC is highly lipophilic and is quickly distributed to all fatty tissues, including the brain. It is also characterized by an entero‑hepatic cycle and renal reabsorption which results in persistent effects. In a driving simulator study, a significant linear correlation was found up to seven hours following absorption, particularly on the trajectory control.

D9THC undergoes oxydative metabolism resulting in the production of various elements, in particular 11‑hydroxy‑tetrahydrocannabinol (11‑OH D9THC) a psychoactive metabolite which, transported by albumin, whereas D9THC attaches mainly to lipoproteins, penetrates the brain more deeply than D9THC; 8 b‑hydroxy‑D9‑tetrahydrocannabinol, potentially psychoactive but whose action would be negligible; and various other components not known for their psychoactive effects. In addition to the potentially psychoactive elements, cannabis contains approximately 200 derivatives of combustion and pyrolysis comparable to those found in tobacco, though some of which are highly carcinogenic and are more concentrated in cannabis smoke than tobacco smoke.

Cannabinoids are eliminated in various ways: through digestion, the kidneys and perspiration. Approximately 15% to 30% of D9THC in the blood is eliminated in urine, 30% to 65% through stools. Because it binds strongly to tissues, D9THC is eliminated slowly in urine: the urine of regular heavy users contains traces of D9THC‑COOH 27 days after they have last used cannabis.

Regular users metabolize D9THC up to twice as fast as individuals who have never previously used the drug. One study showed, in particular, that the intravenous administration of one 5 mg dose of D9THC resulted in higher blood levels in regular users than occasional users.[43]

Cannabinoids act on the body through the endogenous cannabinoid system, consisting of neurochemical substances (endogenous ligands) and specific receptors. The behavioural and central effects of cannabis are due to the agonistic action of its main ingredients (in particular D9THC, exogenous cannabinoid), on the endogenous cannabinoid receptors (anandamide, 2‑arachidonoylglycerol) present in the nervous tissues of the brain.

Although the chemical structure of D9THC was identified by Mechoulam in 1964,[44] it wasn't until very recently that the characteristics and location of the endogenous cannabinoid system was determined.[45] Two types of cannabinoid receptors have been isolated: CB1 in 1990[46] and CB2 in 1993.[47] CB1 is mainly expressed in the central and peripheral nervous system. CB2 is expressed essentially in the cells of the immune system. It follows from this distribution that CB1 is essentially involved in psychotropic effects and CB2 in immunomodulatory effects.

The main endocannabinoids are arachidonoylethanolamide (also called anandamide - a word derived from Sanskrit, literally meaning congratulated) and 2‑arachidonoylglycerol (2‑AG). These are the only two endogenous molecules known to be capable of binding to cannabinoids receptors CB1 and CB2 and replicating the pharmacological and behavioural effects of D9THC. Anandamide levels in the brain are comparable to those of other neurotransmitters such as dopamine and serotonine. The highest levels corresponding to high CB1 density areas, that is to say the hippocampus, striatum, the cerebellum and the cortex. Like anandamide, 2‑AG reproduces all the behavioural effects of D9THC or anandamide, but its action is less powerful.

The CB1 receptors are among the most abundant neuronal receptors in the central nervous system, and their distribution correlates remarkably with the behavioural effects of cannabinoids on memory, sensory perception and control of movements, as shown in the table below.



Location of CB1 receptors in the CNS and correlated pharmacological effects [48]



Physiological consequences




Olfactory systems

Cerebral cortex

Basal nuclei







Grey nucleus


Optic nuclei

Black substances/ventral tegmental area



Grey periaqueductal area

Locus ceruelleus


Bridged nucleus






















Cognitive effects

Locomotive effects

Cognitive effects (short-term memory inhibition) and antiepileptic action

Endocrine and antinociceptive effects









Antinociceptive effects




No lethal dose, no acute mortality

Motor effects (balance)

Herkenham et al., 1990

Herkenham, 1992

Tsou et al., 1998, 1999

Katona et al., 1999

Rinaldi‑Carmona et al., 1996

Matsuda et al., 1990, 1993

Hohmann, 1999

Marsiaco and Lutz, 1999

Westlake et al., 1994

++: abundant marking; +: intermediate marking; ‑: little or no marking.



This concentration of CB1 receptors largely explains the effects of D9THC. Intense expression of CB1 receptors in the basal nucleus and molecular layer of the cerebellum is thus consistent with the inhibiting effects of cannabinoids on psychomotor performance and motor coordination. Their expression in the cortex and hippocampus is consistent with the modulation of elementary forms of learning, explaining in particular the reversible deleterious effects on short-term memory and cognitive function. Their lack of marking in the brainstem explains the absence of acute toxicity or lethal doses of cannabis derivatives. The CB1 receptors in the thalamocortical system participate in the sensory disturbances and analgesic properties of cannabis. Similarly, the presence of receptors in the periaqueductal area and the dorsal horn of the spinal cord contribute to its antinociceptive power.

We also note that the CB1 receptors do not merely inhibit brain function. As a result of circuit effects, cannabinoids can stimulate certain neuron populations, in particular dopaminergic cells in the mesolimbic pathway. Together with the observation that prolonged treatment with cannabis (at doses corresponding to the equivalent of 575 cannabis cigarettes a day!) appears to induce lasting adaptive changes to the central nervous system and to the positive relationship between cannabinoids and stress hormones (corticotrophine), this explains the difficulties (irritability, sleep disorders and so on) observed in regular users when they have stopped using cannabis. We return to this issue in the Chapter 7 in the discussion on cannabis tolerance and dependence.

Lastly, recent works suggest there are significant interindividual variations in the effects of cannabinoids depending on sex steroid hormones in men and women: it appears that the effects of exogenous and endogenous cannabinoids can be modulated by the hormonal state of each individual and that, in exchange, the CB1 receptors and endocannabinoids are able to regulate hormonal activity.

As was observed in the WHO report in 1997, various research questions remain unanswered, in particular how and to what extent cannabis use alters the endogenous cannabinoid and what the relationship is between blood plasma cannabinoid levels and induced behavioural effects.









In conclusion, the Committee makes the following findings:


Conclusions of Chapter 5

On production

















Ø      The size of the cannabis market is estimated at 800 tonnes a year.

Ø      The size of the national production has significantly increased, and it is estimated that 50% of cannabis available is now produced in the country.

Ø      The main producer provinces are British Columbia, Ontario and Quebec.

Ø      Estimates of the monetary value of the cannabis market are unreliable. For example, if 400 tons are grown yearly in Canada, at a street value of $225 per ounce, the total value of the Canadian production would be less than $6 billion per year, less than the often quoted value of the BC market alone.

Ø      An unknown proportion of national production is exported to the United States.

Ø      A portion of production is controlled by organized crime elements.


Ø      THC is the main active ingredient of cannabis; in its natural state, cannabis contains between 0.5% and 3% THC.

Ø      Sophisticated growing methods and genetic progress have made it possible to increase THC content in recent years, but it is impossible to estimate the average content of cannabis available in the market; it is reasonable to consider that content varies between 6% and 31%.

Ø      THC is fat soluble and readily spreads in the innervated tissues of the brain; it reaches a peak in the blood plasma in less than nine minutes and falls to approximately 5% after one hour.

Ø      The body is slow to eliminate THC and inactive THC metabolites can be detected in urine up to 27 days after use in the case of regular users.

Ø      Psychoactive effects generally last two to three hours and as many as five to seven hours after use.







[1]  See in particular INSERM (2001) Cannabis. Quels effets sur le comportement et la santé ? Paris: Les Éditions Inserm, page 143 passim; Ben Amar (in preparation); Wheelock, B.B. (2002) Physiological and Psychological Effects of Cannabis: Review of the Findings. Report prepared for the Senate Special Committee on Illegal Drugs, Ottawa: Senate of Canada.

[2]  This section draws freely on various papers, in particular those by Ben Amar (in preparation), of INSERM, op. cit., and Pelc, I., (2002) (ed.) International Scientific Conference on Cannabis, Brussels. In particular, we wish to thank Professor Ben Amar for his permission to reproduce the plates.

[3]  On these questions, see in particular: McKim W.A. (2000) "Cannabis" in McKim, W.A. (ed.) Drugs and Behaviour. An Introduction to Behavioral Pharmacology. Upper Saddle River: Prentice Hall; Health Canada (1990) Straight Facts About Drugs and Drug Abuse. Ottawa: Department of Supply and Services; and Comité permanent de lutte à la toxicomanie (2001) Drogues. Savoir plus. Risquer Moins. (Édition québécoise) Montréal: Stanké.

[4]  United Nations Office for Drug Control and Crime Prevention (2001) World Drug Report 2001. Oxford: Oxford University Press, pages 30‑32. Available on line at‑01‑22_1.pdf.

[5]  Labrousse, A. (2000) Drogues. Un marché de dupes. Paris: éditions alternatives; see also "L’approvisionnement des marchés des drogues dans l’espace Schengen." Les Cahiers de la Sécurité Intérieure, 32, 2e trimestre 1998.

[6]  See, for example, in OGD (1996) Atlas mondial des drogues. Paris: PUF.

[7]  Royal Canadian Mounted Police (2002) Drug Situation in Canada (2001). Ottawa: author.

[8]  Royal Canadian Mounted Police (2000) Drug Situation in Canada (1999). Ottawa: author.

[9]  UNDCP (2000) op. cit.

[10]  The Committee invited the Executive Director of UNDCP or a delegate to testify before it, but the invitation was turned down.

[11]  "Stumbling in the Dark", The Economist, July 28 - August 3, 2001.

[12]  Royal Canadian Mounted Police (2000), op.cit.

[13]  World Geopolitics of Drugs (1999) Annual Report 1998/1999. Paris: WGD, page 178.

[14]  Greater Toronto Area Combined Forces Special Unit (2002) Fact Sheet - Heroin. Available on line at:

[15]  Mr. Paul Kennedy, Testimony before the Senate Special Committee on Illegal Drugs, June 10, 2002.

[16]  Ibid.

[17]  Royal Canadian Mounted Police (2000) op. cit..

[18]  National Post, May 17, 2002. The Committee is interested, and somewhat amused, to note that this article and a previous report on the Global television network on May 13, 2002, outlining the concerns of American representatives, followed the Committee's publication of its Discussion Paper.

[19]  International Narcotics Control Board (2001) Report of the International Narcotics Control Board for 2000. Available on line at:

[20]  Royal Canadian Mounted Police (2000) op. cit..

[21]  RCMP, private meeting.

[22]  Technique whereby the roots are suspended and sprayed regularly with water enriched with nutrient material, still very rare and the effectiveness of which remains to be proven. (Source: RCMP (2002)).

[23]  RCMP, Drug Situation in Canada (1999) op. cit..

[24]  See in particular Grinspoon, L. and J.B. Bakalar (1997) Marijuana. The Forbidden Medicine. New Haven and London: Yale University Press; Clark P.A. (2000) "The ethics of medical marijuana: government restrictions vs. medical necessity", Journal of Public Health Policy, 21: 40‑60; as well as Wheelock (2002) for the Senate Committee.

[25]  Gaoni, Y. and R. Mechoulam (1964) "Isolation, structure and partial synthesis of an active constituent of hashish", Journal of the American Chemistry Society, 86: 1646‑1647; and Mechoulam, R. and Y. Gaoni (1965) "A total synthesis of delta‑9‑tetrahydrocannabinol, the active constituent of hashish", Journal of the American Chemistry Society, 87: 3273‑3275.

[26]  Smith, D.E. (1998) "Review of the American Medical Association Council on Scientific Affairs Report on Medical Marijuana", Journal of Psychoactive Drugs. 30: 127‑136; McKim W.A. (2000) "Cannabis", in McKim, W.A. (ed.) Drugs and Behavior. An introduction to behavioral pharmacology. Upper Saddle River: Prentice Hall.

[27]  Ashton, C.H. (2001) "Pharmacology and effects of cannabis: a brief review", British Journal of Psychiatry. 178: 101‑106.

[28]  Huestis, M.A et al. (1992) "Characterization of the absorption phase of marijuana smoking", Clinical Pharmacology and Therapeutics, 52: 31‑41.

[29]  Note, for example, that, in the United States, there is no systematic method for measuring THC. As emphasized in a comparative analysis of changes in price of heroin, cocaine and marijuana, "Another problem is that the DEA does not test marijuana for THC content, so there is no marijuana counterpart to the pure grams reported for cocaine and heroin. The difficulty this causes is the STRIDE data provide no basis for adjusting price changes for marijuana’s quality." Abt Associates (2001) The Price of Illicit Drugs: 1981 through the Second Quarter of 2000. Washington, DC. Report prepared for the Office on National Drug Control Policy.

[30]  Testimony of Mchael J. Boyd, Chair of the Drug Abuse Committee and Deputy Chief of the Toronto Police Service, for the Canadian Association of Chiefs of Police, Senate Special Committee on Illegal Drugs, Issue No. 14, page 74.

[31]  Royal Canadian Mounted Police (1999), Annual Report.

[32]  Wayne, H. and S. Wendy (2000) "The THC content of cannabis in Australia: evidence and implications", Australian and New Zealand Journal of Public Health. 24: 503‑508.

[33]  Ibid., page 504.

[34]  Roques, B. (1999) La dangerosité des drogues. Paris: Odile Jacob.

[35]  INSERM (2001) Cannabis: quels effets sur le comportement et la santé? Paris: Les Éditions Inserm.

[36]  Dr. John Morgan, Professor at the City University of New York Medical School, testimony before the Senate Special Committee on Illegal Drugs, June 11, 2001, Issue No. 4, page 29.

[37]  ElSohly, M.A., et al. (2000) "Potency trends of delta9‑THC and other cannabinoids in confiscated marijuana from 1980‑1997", Journal of Forensic Sciences, 45(1): 24‑30.

[38]  Sergeant Dale Orban, Regina Police, at the Senate Committee hearing on May 28, 2001.

[39]  National Post, May 17, 2002.

[40]  World Health Organization (1997) Cannabis: a health perspective and research agenda. Geneva: WHO, 1997. On line at:

[41]  This section is based to a large extent on the INSERM 2001 report as well as the European scientific report 2002 and the survey work done by Wheelock 2002 for the Committee.

[42]  INSERM (2001) Cannabis. Quels effets sur le comportement et la santé? Paris: author, page 340.

[43]  Cited in INSERM (2001) op. cit., page 148.

[44]  Guoli and Mechoulam (1964) op. cit.

[45]  Devane, W.A. et al. (1992) "Isolation and structure of a brain constituent that binds to the cannabinoid receptor", Science, 258 (5090): 1946‑1949.

[46]  Matsuda, L.A. et al. (1990) "Structure of a cannabinoid receptor and functional expression of the cloned DNA", Nature, 346(6284) 5561‑564.

[47]  Munro, S. et al. (1993) "Molecular characterization of a peripheral receptor for cannabinoids", Nature, 365: 61‑65. Note that a recent scientific conference of the National Institute on Drug Abuse in the United States reported on the work of researchers on the hypothesis that there are additional receptors and other ligands. To our knowledge, the latter have not yet been formally identified in the research setting.

[48]  Table reproduced from INSERM (2001), op. cit., page 298.

Previous DocumentNext Document
Top of document