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Marijuana use by Canadian teens among the highest
in the world
Although the "legal" drugs, alcohol and
tobacco, are more popular, marijuana is the most commonly used illegal
drug by young people around the world. Marijuana use represents about
90% of all illicit drug use among students in the US and Australia,
and almost 95% in Europe. Nowhere is marijuana more popular among
students than in Canada. Canadian youth (along with youth in Australia,
France, Ireland, UK and the US) are among the highest consumers of
marijuana in the world.
| |
Ontario, Canada |
Australia |
USA |
Europe - high(France) |
Europe - low(Romania) |
| Lifetime (ever) |
42.7% |
42.8% |
40.9% |
35% |
1% |
| Recent (past year) |
36.4% |
35.25% |
32.1 |
31% |
1% |
A small percentage (3%) of Ontario students reported
using marijuana daily in 2001; this translates into more 27,000 students.
In the same survey, more than half of all marijuana users, representing
about 20% of all students, reported that they had experienced at least
one of three indicators of dependence.
Information on marijuana use among students outside Ontario is sketchy.
Use of marijuana in the past year in the Atlantic Provinces ranged
from 22% to 38% in 1998, while in Manitoba, 39% of students reported
past year use. From these figures, it is clear that many young people
in Canada and elsewhere in the world try marijuana at least once in
high school and many students have used it recently.
Percentage of high school students using Marijuana
in the past year in several provinces
| Province |
% |
| Newfoundland |
30% |
| Nova Scotia |
38% |
| Prince Edward Island |
23% |
| New Brunswick |
30% |
| Ontario |
30% |
| Manitoba |
38% |
| Do possession laws make a difference to young
people?
In Canada and a number of other countries,
there is much discussion around reducing penalties for simple possession
(small amounts for personal use) of marijuana products. The thinking
is that the penalties (i.e. a criminal record) should not represent
a greater harm than the effects stemming from the use of the drug
itself. Under current legislation, the offence of simple possession
of 30g or less of marijuana (a typical joint contains between 0.5and
1g of marijuana) will not typically result in a criminal record, whereas
possession of larger amounts could.
According to a Canadian study, police exercise a great deal of discretion
when apprehending young people for marijuana possession. For small
amounts, police are reported to generally throw out the marijuana,
warn the young person or detain them briefly before releasing them.
To the extent that this is the case, a change in laws toward a fine
for marijuana possession, as is often proposed, would in practical
terms increase the penalty. It appears that the most important impact
of this type of change would be to "clarify the rules" for
everyone, providing police with clear guidance, and a clear message
to young people that possession is not acceptable and will be dealt
with in a consistent way.
At any rate, marijuana laws appear to have limited impact with young
people. It is not completely clear because studies have generally
not looked at arrest rates along with laws (one study that did look
at arrest rates showed that increased arrest rates resulted in slightly
less use among adults, and no effect with adolescents). |
Factors that influence the effects of marijuana
The way it is prepared and used: Marijuana, the leafy
preparation of the marijuana plant, has less tetrahydrocannabinol (THC) than the
resin (hashish) or oil (hash oil). Marijuana that is eaten (for example, in baked
goods) will have one-half to one-third the effect of the same amount smoked. Mental
effects start within minutes of smoking and 30-90 minutes after eating. Most effects
are gone within 3-4 hours (4-8 hours after eating).
The size of the dose: It is very difficult to determine the amount of THC
that is actually consumed by each person when a joint is passed around. THC amounts
vary greatly and other factors also come into play, including the number of puffs,
time between puffs, holding time (in the lungs) and lung capacity. Much has been
made of the fact that the marijuana of today is far more potent than in the past.
It is, in fact, generally quite a bit stronger; however, potency of seized marijuana
varies widely and the enforcement community and media tend to highlight the most
extreme cases. The effects of marijuana will ultimately be determined by the amount
taken in and users can adjust their dose of THC by changing the volume of smoke
they inhale with each puff.
The circumstances surrounding use: Vitally important, this refers to the
setting, the motives and expectations, and whether it is combined with some other
intoxicant. |
Negative effects
Physical effects
It appears that marijuana has no clinically relevant
chronic effects on any part of a healthy body, except for the lungs.
This is mainly due to the effects of combustion rather than marijuana
itself (marijuana smoke contains about 50% more of certain carcinogens
than the same amount of unfiltered tobacco). Long-term, heavy use
results in increased symptoms of bronchitis, coughing, and wheezing.
There is no evidence of effects on the human gastrointestinal, endocrine
(regulating hormones and reproduction), or immune systems. Over the
years, studies of marijuana have shown various physical effects, but
these tend to be slight and are associated with doses that are higher
than usual human doses (often in animal studies). THC can cause cardiac
problems in patients already suffering from high blood pressure or
heart disease; however, this potential risk is much lower than with
amphetamines and cocaine.
Mental effects
In some people who are apparently mentally healthy, psychotic symptoms
can be triggered (such as, delusions, paranoid feelings and hallucinations),
but these disappear as the effects of the drug itself wear off. Heavy,
prolonged use is more likely to produce these symptoms on an ongoing
basis (as is the case with alcohol and most other drugs). In these
cases, recovery generally occurs within a week of abstinence - in
cases where the condition does not improve, it is usually because
of an underlying vulnerability that is triggered by the marijuana
use.
Ongoing, heavy marijuana use (indeed, drug use generally) is often
seen in persons with various mental health problems, such as anxiety,
depression, mood disorders, bipolar disorders, and schizophrenia.
Whether use actually triggers these conditions or whether marijuana
is being used to self-medicate these problems is the subject of much
debate; however, there is little doubt that marijuana use could potentially
worsen these conditions. Heavy marijuana use can impair motivation,
but an "amotivational syndrome", described as a loss of
energy and the urge to work, has not been clearly distinguished.
The hallmarks of physical dependence are tolerance and withdrawal,
and they have been demonstrated in human beings. Withdrawal symptoms
include aggressive behaviour, increased anxiety, restlessness, sleep
disturbance, downturns in mood, and loss of appetite. An actual diagnosis
of marijuana dependence involves other criteria, such as continuing
to use knowing the harm that may result from it, and devoting much
time to acquiring, using and recovering from use.
Marijuana dependence does occur, but is not likely to occur in the
usual patterns of social use (that is, when doses are small or infrequent).
The addictive potential of marijuana is considered weaker than that
of many other drugs, including alcohol and tobacco, and dependence
disrupts the user's ability to function less than with other substances.
That said, marijuana dependence among young people does occur, and
can represent a very significant barrier to a young person's development.
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Article
prepared by Gary Roberts for the 
