Discussion Paper

The Senate Committee’s Discussion Paper – Download [PDF – 10 pages]

Frequently Asked Questions about cannabis

  1. Is cannabis a gateway drug?
  2. Does cannabis use create dependency?
  3. What are the health effects of cannabis use?
  4. Is cannabis use related to criminality?
  5. Does cannabis use impair driving abilities?
  6. Are young people victims of cannabis?
  7. What key conclusions emerge from science?
  8. What are the main public policy options?

1. Is cannabis a gateway drug?

Cannabis may induce some people to using other, more potent drugs, as will alcohol or tobacco. This was a recurring concern expressed to the Committee.

In order to confirm or infirm this assertion, rigorous and systematic data on use patterns and histories of users are essential. However, the 2001 report of the Auditor General noted, as did we, that such data on the Canadian population are weak and dated. This is an obvious shortcoming when assessing a policy.

Presuming that Canadian patterns may not differ significantly from those of other countries, we must rely on research from abroad. Studies conducted in Australia, England, France, Netherlands and the USA indicate that the vast majority of cannabis smokers never progress to other drugs. This finding remains constant despite policy differences between these countries. While it is true that most users of hard drugs have also used cannabis before these other drugs, they are also likely to have used alcohol and tobacco at a younger age. Other factors, mainly psychosocial, would better explain progression to other drugs.

Cannabis and the gateway hypothesis

* There is no convincing evidence to establish the gateway hypothesis.

* Data from population surveys show that out of 100 cannabis users in adolescence, about 10 will become regular users and 5 will move to using other drugs.

* Pharmacological studies of cannabis active ingredients have not found any element that predisposes users to more potent drugs. Some studies would show that cannabis may be an effective substitute to treat dependency to hard drugs.

Sources: National Institute of Medicine 1999; Roques, 1999; INSERM, 2001; Cohen & Sas, 1997; ben Amar, in print; National Drug Research Institute, 2000.


 2. Does cannabis use cause dependency?

Cannabis is a drug. Like other drugs, it is a psychoactive substance with toxicological effects which, in some users, will lead to some form of dependency.

Research conducted internationally shows that between 8 to 10% of cannabis users may develop some psychological dependency, a much smaller proportion than for many other drugs, illegal and legal, and comparable to some prescribed medications.

When developed, addiction to cannabis usually does not require therapy and existing forms of therapy have demonstrated their effectiveness. For most dependent users, stopping use for a few days is usually sufficient to eliminate any symptom of addiction. Physical dependence is a rare occurrence.

Cannabis and dependency

* Pharmacological, epidemiological studies and life stories of drug users conducted in many countries show that psychoactive substances rank as follows in terms of their addictive power:- tobacco and heroin: 35% to 50% of users – alcohol and cocaine: 15% to 20% of users – psychoactive medication: 5 to 10% of users – cannabis: 8 to 10% of users.

* Based on the psychiatric criteria defined in the American manual of psychiatry, studies in the USA indicate that around 8% of users develop dependency.

* Dependency rates tend to be higher among younger users (15 to 24) at about 15%.

* Auto-administration in laboratory animals,
generally considered the most objective criterion for inducing dependency, has systematically been found not to occur.

Sources: Roques, 1999; INSERM, 2001; Grinspoon & Bakalar, 1997; Swiss Federal Commission on Drugs, 1999; International Scientific Conference on Cannabis, 2002.


 3. What are the health effects of cannabis use?

Cannabis has been known for over 2000 years and has been used for religious, social as well as medical purposes in various cultures and societies.

Cannabis, like any other drug, has potential negative health effects. But cannabis, like other drugs, also has positive effects. These include relaxation, euphoria and sociability. Cannabis also has therapeutic applications.

Like other drugs – and any addiction prone activity from over-eating to extreme sports – cannabis can cause harm to those using it. In pharmacology, a distinction is made between the acute (short term) and chronic (long term) effect of the drug.

The acute effects include reductions of:

  • attention and concentration
  • motor abilities (reflex, coordination)
  • short-term memory.

Chronic effects, more likely to be found in heavy users, include:

  • increased risk of lung cancer (research has yet to distinguish between effects of cannabis and tobacco) and other respiratory diseases;
  • possibility of cannabinoid psychosis among persons predisposed to psychosis;
  • possibility of amotivational syndrome [apathy, indifference and loss of interest and ambition].

Cannabis and health effects

  • Among recognized therapeutic benefits are: anti-vomiting, anti-spasmodic, and pain management.
  • Some of the chronic somatic effects of smoked cannabis include: increased likelihood of respiratory tract diseases and bronchitis; increased risk of lung cancer.
  • Some of the long-term cognitive effects of cannabis may include reduced attention and memory capabilities.

Cannabis has a very high therapeutic safety index of 40,000: in other words, dying from cannabis overdose is close to impossible.

Sources: National Institute of Medicine, 1999; INSERM, 2001.


 4. Is cannabis use related to criminality?

Many of us perceive that a significant proportion of ordinary criminality is related to drugs. Alcohol abuse is significantly related to increased aggression (notably inside the family). Abuse of some illegal drugs is associated with such crimes as residential burglary, car theft and street prostitution, in part to pay for the daily doses. Nevertheless, the relationship between drugs and crime is more complex than often thought.

Research indicates that this relationship does not apply in the case of cannabis, that cannabis use does not lead to the commission of crime with two exceptions. Because it is illegal, cannabis production and distribution is partly controlled by organized crime. The second exception is driving a vehicle under the influence of cannabis.

Cannabis users are considered “criminals” as they are in possession of a prohibited substance. Every year, about half of all drug charges are cannabis offences. While total Criminal Code offences have diminished in Canada each of the last 8 years, drug related offences have increased. It is impossible to estimate the total costs of cannabis criminalization. The most recent Auditor General’s Report mentions that the annual cost of fighting illegal drugs for federal agencies only is over $500 million.

Cannabis and crime

  • Cannabis use does not induce users to commit other forms of crime
  • Cannabis use does not increase aggressiveness or anti-social behaviour.
  • Over one and a half million Canadians have a criminal record for simple cannabis possession.
  • In 2000, over 30,000 persons were accused of simple cannabis possession.
  • Cannabis possession offences represent over 50% of all drug related offences reported by police.
  • Overall, traffic and importation offences have diminished during the 1990’s.

Sources: Statistics Canada, 2000; Brochu, 1995; Erickson, 1980 & 1986; Casavant & Collin, 2001; Ati-Dion, 1999 & 2000.


5. Does cannabis use impair driving abilities?

No one wants to repeat the experience we have had with motor vehicles and alcohol. At this time there is no recognized tool for the police to detect the level of THC in blood as there is for alcohol.

Cannabis, like other drugs, impairs motor and coordination abilities. Yet studies are inconclusive and unable to distinguish between the effects of alcohol and those of cannabis. Laboratory studies indicate that driving abilities are affected for a period of 2 to 8 hours after ingestion of cannabis. Laboratory studies also indicate that drivers under the influence of cannabis are more cautious and less aggressive and drive more slowly than drivers under the influence of alcohol. Studies on pilots have revealed a significant reduction in abilities under the influence of marijuana, without them being conscious of impairment.

Cannabis and driving

  • Available epidemiological studies do not allow to reach definitive conclusions on the effects of cannabis on driving abilities;
  • However, studies tend to indicate that at high doses or combined with alcohol, cannabis use increases risks significantly;
  • Cannabis use impairs motor coordination as well as straight line control and continued attention;
  • However, cannabis use decreases average speed, and diminishes risk-taking behaviour.

Sources: INSERM, 2001; Robbe, 1994; International Scientific Conference on Cannabis, 2002.


 6. Are young people victims of cannabis?

The health and well-being of youth are key considerations in setting cannabis policy. Some witnesses before the Committee and individuals writing to us are concerned that a more “liberal” drug policy would mean increased use, especially by youth.
Studies show that youth are already the principal user group, though Canadian data are weak and inconsistent. Surveys of high school students in Ontario and Quebec reveal that close to 50% of them have used cannabis at least once during the past year, similar to findings in European surveys.

Studies also show that in the Netherlands, despite its more liberal approach than in most other countries, the proportion of youth using cannabis is not higher. In fact, it is in the middle of the pack.

Does cannabis use affect academic performance or social abilities? Studies tend to indicate that problem young cannabis users are also problem alcohol users, manifesting other “risk-taking” behaviour. These are therefore symptoms of other underlying problems, rather than causes.

Cannabis and youth

  • In some Canadian studies, some 30% of 15- 16 year olds report having used cannabis in the past month.
  • Last year prevalence among the 12-19 is estimated at around 16%. Similar proportions are found in the USA, England, and France. In Portugal and Sweden it is much lower (about 8%).
  • Use tends to peak at around 19 and gradually declines after 25.
  • Studies tend to indicate that the proportion of youth using cannabis has increased over the past five years.
  • Studies indicate that there would be an increase also in poly consumption (using multiple substances) among youth.
  • Studies indicate that about 10% of young people using cannabis can be considered as problem users (using alone, in the morning, repeatedly).
  • Studies tend to indicate that problem users also experience other types of problem behaviour (e.g., school drop-out or truancy)

Sources: CCSA, 1999; EMCDDA, 2001; CAMH, 2000; Zoccolillo et al. 1999 ; OFDT, 2000.


 7. What key conclusions emerge from science?

Scientific research we have examined to date indicates that:

  • Cannabis is a psychoactive substance and it is therefore better to not use it.
  • The vast majority of recreational users use cannabis only temporarily and irregularly; approximately 10% become chronic users and 5 to 10% become addicted.
  • Cannabis may have some negative effects on the health of individuals, but considering the patterns of use, these effects are relatively benign.
  • Cannabis has very limited effects on public safety insofar as ordinary crime is concerned. However, its illegal status contributes to fuelling organized crime elements. Impaired driving under the sole influence of cannabis has not been established firmly in research although it likely affects driving abilities.
  • Each year, over 30,000 Canadians are charged by police for simple cannabis possession;
  • Over 1 Canadian in 10 and 30% to 50% of youth aged 15-24 have used cannabis in the last year despite its illegality; this may cause greater disrespect for the rule of law;
  • The illegality of cannabis means significant expenditure of public funds, particularly for law enforcement; it also means less information and prevention action is undertaken.

8. What are the main public policy options?

Much to our surprise, research indicates that public policies have little impact on use levels and patterns. They may, however, have effects on use contexts. Prohibition and criminalization entail a criminal record for simple cannabis possession, fuel a black market that brings young people into contact with criminal elements and force them to hide to avoid police scrutiny.

Public policies also entail other negative effects. Prohibition makes public health approaches, balanced information, prevention, and quality control of substances difficult if not impossible. Users receive little information on the effects of the substances and are not informed about the quality from reliable sources. Criminalization benefits organized crime, increasing its wealth, power and possibility of corruption.

National policies on drugs find much of their legitimacy in the international conventions and treaties signed since the 1912 Hague Convention. Yet, to a large extent, these international agreements evolved in the absence of any significant drug problem in developed countries that pushed them. For example, the 1961 Single Convention was developed and adopted long before the youth movements and drug use explosion in Western countries at the end of the 1960’s.

Public policy and use patterns

public policy and use patterns chart

Whether countries are prohibitionist such as Canada, Sweden or the USA or more liberal as in Australia, The Netherlands or Spain, levels and patterns of use vary according to other factors and are little influenced by the policy.

Sources: INSERM, 2001; MacCoun et Reuter, 1997; Cohen et.al, 2001; EMCDDA, 2001; Kilmer, 2002.


“Public policy options: What are your views?”
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"Public policy options: What are your views?" (preview)

Preview of: “Public policy options: What are your views?”
The worksheet that accompanied the Senate Committee’s May 2002 Discussion Paper. Download the worksheet [Word format]

Basic terminology

Abuse: vague term. Some think that any use is abuse. It is more pertinent to distinguish between use, risk behaviour or addictive behaviour and abuse.

Cannabis: plant from which are produced marijuana (dried leaves, stems and floral summits), haschish (resin of the plant), and cannabis oil.

Decriminalisation: generally refers to removing dispositions from the Criminal Code. With respect to cannabis, some countries have adopted a policy to decriminalize in practice but not in law (referred to as de facto decriminalization), where simple possession cases are no longer prosecuted.

Dependence: modification of the nervous (physical dependence) or emotional system (psychological dependence) resulting from the reduction of use following continued and repeated use.

Legalisation: opponents to prohibition are often presented as “legalizers”. In this approach, use and possession of cannabis for personal use are allowed (while some form of interdiction is maintained for sales to minors, traffic, etc.). No country has yet adopted this approach.

Psycho-active substance: refers to any substance modulating the psyche of individuals and leading to changes in perceptions, conscience, mood, etc. Includes tobacco, alcohol, numerous prescribed medication and illicit substances.

THC: tetrahydrocannabinol, the active ingredient in cannabis. Although estimates vary considerably, it is usually found in concentration of 8% to 10% in cannabis and up to 15% in haschich.