APPENDIX

R. v. CLAY and PRENTICE

Addendum To The Judgment Of Mccart J. F.

DATED AUGUST 14, 1997

CANNABIS COMMISSION REPORTS

A Summary Of The Potential Harms & Benefits

Prepared by Chris Clay May 17, 1997

Report of the Indian Hemp Drugs Commission (India, 1893 1894)

*The excessive consumers then must be regarded as bearing but a small
proportion to the moderate - certainly not more than 5 per cent, or 1 to
20. (p. 130)

*Cannabis indica must be looked upon as one of the most important drugs of
Indian Materia Medica. (p. 175)

*But long-continued smoking, whether of ganja or of any other substance,
doubtless results in the deposition of finely divided carbonaceous matter
in the lung tissues, and the presence of other irritating substances in the
smoke ultimately causes local irritation of the bronchial mucous membrane,
leading to increased secretion, and resulting in the condition which is
described as chronic bronchitis in ganja smokers. (p. 177)

*The vast majority assert that in some one or other their forms [cannabis]
may produce at least temporarily beneficial effects. Many even of those who
regard the use of the drugs as on the whole baneful admit such temporary
benefits. (p. 181)

*The drugs are said to be cheering in their effects, and to be prized by
many on this account. (p. 182)

*[T]here are very few witnesses who even profess to have any experience of
evil effects resulting from moderate consumption. (p. 183)

*The truth seems to be that while, no doubt, these drugs are more commonly
consumed merely as stimulants than from any clearly defined idea of their
beneficial results, yet they are popularly believed to have (if moderately
used) some such beneficial results as have been described above. Moderate
consumers believe this, and would feel a sense of deprivation if they were
unable to obtain what they regard as a beneficial stimulant. This
deprivation would be more felt among the poorer classes than among the
wealthier, whose tastes lead them to more expensive luxuries. (p. 183)

*The experience of our jails seems clearly to confirm the general opinion
that the opium habit takes a much stronger hold than the ganja habit, and
that no injurious physical effects follow the compulsory cessation of the
latter. (p. 185)

*In the absence of all physiological evidence of tissue changes being
produced by these drugs, as they are produced by alcohol, it must be
presumed, until the contrary appear, that the moderate use does not cause
injury in any but the most exceptional cases. (p. 202)

*The medical evidence which has thus been analyzed very clearly indicates
in the opinion of the Commission that when the basis of the opinions as to
the alleged evil effects of the moderate use of the drugs is subjected to
careful examination, the grounds on which the allegations are founded prove
to be in the highest degree defective. (p. 223)

*The most striking feature of the medical evidence is perhaps the large
number of practitioners of long experience who have seen no evidence of any
connection between hemp drugs and disease. (p. 223)

*As in long-continued and excessive cigarette smoking considerable
bronchial irritation and chronic catarrhal laryngitis may be induced, so,
too, may a similar condition be caused by excessive ganja or charas
smoking. (p. 223)

*Altogether it is clear that the moderate consumer is as a rule perfectly
inoffensive. There appear to be quite adequate grounds for accepting the
statement of those who assert that as a rule he "cannot be distinguished
from the total abstainer." (p. 255)

*[A] majority of eight to one hold that moderate consumption of these drugs
has no connection with crime in general or with crimes of any particular
character. A majority of nearly four to one hold the same view in regard to
excessive consumption. ... [T]he general opinion is that hemp drugs have
per se no necessary connections with crime. (p. 256)

*There seems, therefore, good reason for believing that the connection
between hemp drugs and ordinary crime is very slight indeed. (p. 257)

*It has been clearly established that the occasional use of hemp in
moderate doses may be beneficial; but this use may be regarded as medicinal
in character. ... In regard to the physical effects, the Commission have
come to the conclusion that the moderate use of hemp drugs is practically
attended by no evil results at all. ... Speaking generally, the Commission
are of the opinion that the moderate use of hemp drugs appears to cause no
appreciable physical injury of any kind. (p. 263)

*In respect to the alleged mental effects of the drugs, the Commission have
come to the conclusion that the moderate use of hemp drugs produces no
injurious effects on the mind. (p. 264)

*In regard to the moral effects of the drugs, the Commission are of the
opinion that their moderate use produces no moral injury whatever. There is
no adequate ground for believing that it injuriously affects the character
of the consumer. (p. 264)

*Viewing the subject generally, it may be added that the moderate use of
these drugs is the rule, and that the excessive use is comparatively
exceptional. The moderate use practically produces no ill effects. (p. 264)

The Marihuana Problem in the City of New York (The "LaGuardia Report")
(U.S.A., 1944) Reprinted in "The Marihuana Papers", Edited by David Solomon

*The confirmed marihuana smoker ... appears to be quite conscious of the
quantity he requires to reach the effect called "high." Once the desired
effect is obtained he cannot be persuaded to consume more. He knows when he
has had enough. The smoker determines for himself the point of being
"high," and is ever-conscious of preventing himself from becoming "too
high." (p. 250)

*We have been unable to confirm the opinion expressed by some investigators
that marihuana smoking is the first step in the use of such drugs as
cocaine, morphine, and heroin. The instances are extremely rare where the
habit of marihuana smoking is associated with addiction to these other
narcotics. (p. 250)

*During our investigation many law enforcement officers, representing
various federal, state and local police bureaus, were interviewed and asked
for a confidential expression of opinion on the general question of crime
and marihuana. In most instances they unhesitatingly stated that there is
no proof that major crimes are associated with the practice of smoking
marihuana. (p.

*The practice of smoking marihuana does not lead to addiction in the
medical sense of the word. (p. 259)

*The use of marihuana does not lead to morphine or heroin or cocaine
addiction and no effort is made to create a market for these narcotics by
stimulating the practice of marihuana smoking. (p. 260)

*The publicity concerning the catastrophic effects of marihuana smoking in
New York City is unfounded. (p. 260)

*[I]t is noteworthy that in none of the descriptions is there found an
expression of antagonism or antisocial behaviour which led to acts of
violence or what would be called criminal conduct. (p. 262)

*Indulgence in marihuana does not appear to result in mental deterioration.
(p. 312)

*It is important to note that neither the ingestion of marihuana nor the
smoking of marihuana cigarettes affects the basic outlook of the individual
except in a very few instances and to a very slight degree. In general the
subjects who are withdrawn and introversive stay that way, those who are
outgoing remain so, and so on. Where changes occur the shift is so slight
as to be negligible. In other words reactions which are natively alien to
the individual cannot be induced by the ingestion or smoking of the drug.
(p. 334)

*Under the influence of marihuana the basic personality structure of the
individual does not change but some of the more superficial aspects of his
behaviour show alteration. (p. 335)

*Furthermore, those who have been smoking marihuana for a period of years
showed no mental or physical deterioration which may be attributed to the
drug. (p. 358)

*From limited observations on addicts undergoing morphine withdrawal and on
certain types of psychopathic disturbances, the impression was gained that
marihuana had beneficial effects, but much more extensive and controlled
study is required for definite conclusions to be drawn concerning
therapeutic usage. (p. 359)

*The typical effects of marihuana on man are ascribed to actions on the
central nervous system. In dogs, the characteristic effect is ataxia. ...
In rabbits a characteristic effect of marihuana extracts is corneal
areflexia. (p. 359)

The President's Commission on Law Enforcement and Administration of Justice
Task Force Report: Narcotics and Drug Abuse (U.S.A., 1967)

*Its effects are rather complicated, combining both stimulation and
depression. Much of its effects depends on the personality of the user. ...
Tolerance is very slight if it develops at all. Physical dependence does
not develop. (p. 3)

*Marihuana is equated in law with the opiates, but the abuse
characteristics of the two have almost nothing in common. The opiates
produce physical dependence. Marihuana does not. A withdrawal sickness
appears when use of the opiates is discontinued. No such symptoms are
associated with marihuana. The desired dose of opiates tends to increase
over time, but this is not true of marihuana. Both can lead to psychic
dependence, but so can almost any substance that alters the state of
consciousness. (p. 13)

*It might, but certainly will not necessarily or inevitably, lead to
aggressive behaviour or crime. The response will depend more on the
individual than the drug. This hypothesis is consistent with the evidence
that marihuana does not alter the basic personality structure. (p. 13)

*The charge that marihuana "leads" to the use of addicting drugs needs to
be critically examined. There is evidence that a majority of the heroin
users who come to the attention of public authorities have, in fact, had
some prior experience with marijuana. But this does not mean that one leads
to the other in the sense that marihuana has an intrinsic quality that
creates a heroin liability. There are too many marihuana users who do not
graduate to heroin, and too many heroin addicts with no known prior
marihuana use, to support such a theory. (p. 13)

*In the United States neither cannabis psychoses nor cannabis dependency
has been described. (p. 24)

*With regard to crime, other than the violation of law occurring by virtue
of acquiring and possessing marihuana, there is no reliable evidence that
marihuana "causes" crime. (pp. 24-25)

*With regard to traffic accidents, data is lacking. ... Effects are no
doubt related to dosage but no studies on varied dosage using driving tasks
have been done. (p. 25)

Cannabis: Report by the Advisory Committee on Drug Dependence (England, 1968)

*Because of the relatively rapid onset when the drug is smoked, experienced
smokers can adjust their dosage to achieve the effect that they seek. (p. 6)

*The taking of cannabis does not normally result in any characteristic
physical effects except that of redness of the eyes. (p. 6)

*The effects of cannabis use in moderate amounts are predominantly
psychological. They begin with a sense of excitement or tension, sometimes
with apprehension or hilarity, followed as a rule by a sense of heightened
awareness: colours, sounds and social intercourse appear more intense and
meaningful. A sense of well-being is then usual. (p. 6)

*Having reviewed all the material available to us we find ourselves in
agreement with the conclusion reached by the Indian Hemp Drugs Commission
appointed by the Government of India (1893 - 1894) and the New York Mayor's
Committee on Marihuana (1944), that the long-term consumption of cannabis
in moderate doses has no harmful effects. (pp. 6-7)

*Witnesses knowledgeable about patterns of use told us that although some
people smoked every day without interference to work or social life, the
typical user probably took the drug once or twice a week, aiming at a
"high" of 2 or 3 hours. (p. 11)

*Several medical witnesses speculated that it had appeared to be beneficial
for young patients during depression and also to have helped ex-addicts to
abstain from heroin. (p. 11)

*It was generally agreed that it was dangerous to drive a motor vehicle
under the influence of cannabis not so much because driving ability was
over-estimated (as with alcohol) as because of possible distortion of
perception of depth and perspective. (p. 11)

*Most observers discount any pharmacological action disposing the
cannabis-smoker to resort to other drugs, and look for other explanations.
Some have suggested that in order to obtain their supplies cannabis-users
must inevitably resort to the criminal underworld where opiates are also
available. (p. 12)

*It can clearly be argued on the world picture that cannabis use does not
lead to heroin addiction. (p. 13)

*Published statements on links between cannabis and crime tend to confuse
the consequences of enforcing legal restrictions on non-conforming drug
users with alleged criminogenic effects of cannabis-smoking itself Since
possession of cannabis is generally prohibited, the user found in
possession automatically acquires a criminal record. To obtain his supply,
an illicit source must also be involved. (p. 13)

*In the United Kingdom the taking of cannabis has not so far been regarded,
even by the severest critics, as a direct cause of serious crime. (p. 14)

*Unlike the "hard" drugs, such as heroin, cannabis does not produce
tolerance. Consuming the same, sometimes even a smaller, amount of cannabis
continues to produce the original effect. Unlike heroin, cannabis does not
cause physical dependence and withdrawal effects do not occur when its use
is discontinued. (p. 14)

*An increasing number of people, mainly young, in all classes of society
are experimenting with this drug, and substantial numbers use it regularly
for social pleasure. There is no evidence that this activity is causing
violent crime or aggressive anti-social behaviour, or is producing in
otherwise normal people conditions of dependence or psychosis, requiring
medical treatment. (p. 16)

*[I]n terms of physical harmfulness, cannabis is very much less dangerous
than the opiates, amphetamines and barbiturates, and also less dangerous
than alcohol. (p. 17)

Marihuana: A Signal of Misunderstanding, Report of the National Commission
on Marihuana and Drug Abuse (The "Shafer Commission") (U.S.A., 1972)

*No conclusive evidence exists of any physical damage, disturbances of
bodily processes or proven human fatalities attributable solely to even
very high doses of marihuana. (pp. 56 - 56)

*These few consistently observed transient effects on bodily function seem
to suggest that marihuana is a rather unexciting compound of negligible
immediate toxicity at the doses usually consumed in this country. (p. 57)

*Performance of simple or familiar tasks is at most minimally impaired,
while poor performance is demonstrated on complex, unfamiliar tasks.
Experienced marihuana users commonly demonstrate significantly less
decrement in performance than drug-naive individuals. (p. 57)

*When the nature of the drug-taking situation and the characteristics of
the individual are optimal, the user is apt to describe his experience as
one of relaxation, sensitivity, friendliness, carefreeness, thoughtfulness,
happiness, peacefulness, and fun. For most marihuana users who continue to
use the drug, the experience is overwhelmingly pleasurable. (p. 58)

*The incidence of psychiatric hospitalizations for acute psychoses and of
use of drugs other than alcohol is not significantly higher than among the
non-using population. (p. 64)

*Another controversial form of social-mental deterioration allegedly
related to very long-term very heavy cannabis use is the "amotivational
syndrome." ... Intensive studies of the Greek and Jamaican populations of
heavy long-term cannabis users appear to dispute the sole causality of
cannabis in this syndrome. (p. 64)

*Looking only at the effects on the individual, there is little proven
danger of physical or psychological harm from the experimental or
intermittent use of the natural preparations of cannabis, including the
resinous mixtures commonly used in this country. (p. 65)

*The experimenter and the intermittent users develop little or no
psychological dependence on the drug. No organ injury is demonstrable. (p. 66)

*Rather than inducing violent or aggressive behaviour through its purported
effects of lowering inhibitions, weakening impulse control and heightening
aggressive tendencies, marihuana was usually found to inhibit the
expression of aggressive impulses. (p. 72)

*No evidence exists that marihuana use will cause or lead to the commission
of violent or aggressive behaviour by the large majority of psychologically
and socially mature individuals in the general population. (p. 73)

*The Commission's National Survey revealed that 48% of adults believe that
some people have died from marihuana use. A careful search of the
literature and testimony of the nation's health officials has not revealed
a single human fatality in the United States to have resulted solely from
ingestion of marihuana. (p. 83)

*In all its studies, the Commission found no evidence of chromosome damage
or teratogenic or mutagenic effects due to cannabis at doses commonly used
by man. However, since fetal damage cannot be ruled out, the use of
marihuana like that of many other drugs, is not advisable during pregnancy.
(p. 84)

*From a public health point of view, the immediate effects of marihuana
intoxication on the individual's organs or bodily functions are of little
significance. (p. 85)

*Minimal abnormalities in pulmonary function have been observed in some
cases of heavy and very heavy smokers of potent marihuana preparations
(ganja or hashish). (p. 85)

*No objective evidence of specific pathology in brain tissue has been
documented. This contrasts sharply with the well-established brain damage
of chronic alcoholism. (p. 85)

*No outstanding abnormalities in psychological tests, psychiatric
interviews or coping patterns have been conclusively documented in studies
of cannabis users in other countries of the world. Further research into
this important area is necessary. (p. 85)

*Whichever interpretation one accepts, the fact is apparent that the
chronic, heavy use of marihuana may jeopardize social and economic
adjustments of the adolescent. (p. 87)

*Marihuana clearly is not in the same chemical category as heroin insofar
as its physiologic and psychological effects are concerned. In a word,
cannabis does not lead to physical dependence. (p. 87)

*Indeed, if any drug is associated with the use of other drugs, including
marihuana, it is tobacco, followed closely by alcohol. ... The fact should
be emphasized that the overwhelming majority of marihuana users do not
progress to other drugs. (p. 87)

*[T]he largest number of marihuana users in the United States today are
experimenters or intermittent users, and 2% of those who have ever used it
are presently heavy users. (p. 88)

*We believe that experimental or intermittent use of this drug carries
minimal risk to the public health, and should not be given overzealous
attention in terms of a public health response. (p. 91)

*In short, aside from his use of marihuana, the adult recreational user is
not generally viewed as a significant social problem. (p. 93)

*Scientific evidence has clearly demonstrated that marihuana is not a
narcotic drug, and the law should properly reflect this fact. (p. 177)

Cannabis: A Report of the Commission of Inquiry into the Non-Medical Use of
Drugs (The "Ledain Commission") (Canada, 1972)

*Cannabis has been widely used in many cultures for its medicinal
properties. Cannabinoids have been used in the past and are presently
employed in some countries (or are currently under clinical investigation)
for their alleged anxiety-reducing, mood-elevating, appetite-stimulating,
anti-convulsant, diuretic, blood pressure-reducing, analgesic
(pain-reducing), sedative and anaesthetic properties. ... Cannabis has also
been used to reduce insomnia, to treat coughs, tetanus, burns, earache, and
migraine headache, to ease opiate narcotic and alcohol withdrawal, and as
an aid in obstetrics and psychotherapy. (p. 32)

*In all, it would seem likely that under some conditions, cannabis might
have adverse effects on driving, and that any such effects would vary as a
function of dose and a variety of other factors. (p. 60)

*[T]here is no evidence from available experiments for the notion that
social cannabis use produces a disastrous loss of judgement or psychomotor
control. Our research suggests that until further data are available,
driving while under the influence of cannabis should be avoided. (p. 64)

*[S]urveys of hospital admissions and resident patients in North America
have uncovered an almost insignificant number of patients with primary
cannabis problems. Even university counselling and health services have a
dearth of systematic records of serious cannabis difficulties. (p. 101)

*Major governmental inquiries around the world for three-quarters of a
century have come to generally similar conclusions regarding the lack of a
causal relationship between cannabis use and major crime. There is no
scientific evidence that cannabis use, itself, is significantly responsible
for the commission of other forms of criminal behaviour. (p. 110)

*Cannabis has exceptionally low lethal toxicity. Few, if any, human deaths
have been caused directly by cannabis overdose. (p. 113)

*Respiratory and bronchial disorders will probably result from heavy
chronic smoking of many crude substances and cannabis seems to be no
exception. (p. 118)

*There is little indication ... that that physical dependence on cannabis
is a likely phenomenon under natural conditions. (p. 123)

*On the whole, the physical and mental effects of cannabis, at the levels
of use presently attained in North America, would appear to be much less
serious than those which may result from excessive use of alcohol. (p. 267)

*We are in general agreement that the regular use of cannabis by
adolescents has, in all probability, a harmful effect on the maturing
process, and that this should be the chief focus of our social concern. (p.
268)

*There is no evidence that the use of cannabis has been a significant cause
of automobile accidents, but at moderate doses it produces significant
impairment of capacities required for driving. (p. 269)

*The evidence of "personality change" of the kind referred to as the
"amotivational syndrome" resulting from the chronic, heavy use of cannabis
is inconclusive. ... It is difficult to distinguish between adverse effect
on capacity and mere change in attitude. ... Some observers have spoken of
apathy and a loss of goals, an absorption in the present with little or no
thought for the future. All of these symptoms might be equally associated
with a profound change of values and outlook which many might regard as
salutary. (p. 270)

*The theory that cannabis leads to heroin because the vast majority of
heroin users are found to have used cannabis has to be dismissed on the
ground of faulty logic: the vast majority of heroin users may have used
cannabis, but the vast majority of cannabis users do not use heroin. (p. 272)

*There has been little evidence in Canada to support an association of
cannabis with crimes of violence. Nor is there any suggestion that cannabis
users are obliged to engage to any significant extent in a career of petty
crime to support their habit ... (p. 273)

Cannabis: A discussion paper by the Royal Commission into the Non-Medical
Use of Drugs (South Australia, 1979)

*It is now clear that cannabis is not a narcotic. While this
misclassification was not necessarily deliberate, since pharmacology was
then a poorly developed science, it was a powerful factor in ensuring the
enactment of prohibitions. (p. 4)

*Despite earlier evidence, there is now very little doubt that with
sufficient quantities and a regular and frequent dosage, tolerance does
develop to cannabis. The dosage levels used on a regular basis by people in
Greece, Costa Rica and Jamaica (where such use has been the subject of
intensive controlled studies) are extremely high ... Despite these high
doses (equivalent to 20 to 40 joints a day) the users showed no evidence of
undue depression or adverse effects. Such a dose in a non-tolerant
individual would be extremely unpleasant. (p. 106)

*Physical dependence on a drug can be determined by a withdrawal syndrome
if the drug is no longer available. Clinical reports of a withdrawal
syndrome from cannabis are extremely rare, and the reported symptoms have
been mild. (p. 106)

*[T]here is certainly no over-riding compulsion to obtain the drug,
regardless of the cost, as there is with narcotics. (p. 107)

*There have been no documented cases of human fatality which can clearly be
attributed to the acute effects of a single dose of cannabis. The
concentration of THC in cannabis, for example, means that it would be
extremely difficult - if not impossible - to take a lethal dose. (p. 107)

*Pharmacologically, THC has a very wide margin of safety - that is, there
is a huge difference between the amount needed for a social high and the
amount needed to produce death. In fact, even the amount necessary to
produce hallucinations is at least five times greater than that required
for a social high ... By comparison, a dose of alcohol five times greater
than that normally consumed for a social high may produce coma and death.
(p. 108)

*Unlike alcohol, cannabis is not accompanied by a hangover - there is no
'morning after' effect other than a feeling of lethargy if one has smoked a
large quantity. (p. 111)

*The general effects of cannabis can be described as producing a state of
well-being, relaxation and sedation. The effect usually includes an
apparently stimulatory phase when euphoria and excitement are experienced
and spontaneous laughter is common. Perceptual awareness is increased.
Sudden mood changes can occur, and short-term memory and some cognitive
processes are adversely affected. Of course, these effects may be desirable
from the user's point of view. ... Both the psychological and physiological
effects are short-lived. (p. 115)

*To date the most promising avenue for the medical use of cannabis is in
the treatment of glaucoma. (p. 116)

*Several researchers have described the effects of THC on dilating the main
respiratory tubes, thus suggesting its possible use for asthma patients.
(p. 116)

*Cannabis has a long history of use as an analgesic and in recent studies
with experimental animals, THC has been shown to compare favourably with
pethidine and morphine. (p. 116)

*THC has been found to be effective in reducing the incidence of nausea and
vomiting associated with the present methods of cancer treatment. A recent
study suggested that the drug has a beneficial effect on the symptoms of
depression, pain, nausea and vomiting and reduces loss of body weight - all
of which may reduce the suffering associated with terminal cancer. (p. 116)

*A number of studies have been concerned with the effects of cannabis on
those motor and mental skills considered important for driving a motor
vehicle. The results indicate quite strongly that intoxication with
cannabis may adversely affect ability to drive a car safely. (p. 117)

*South (1978) suggests that drivers under the influence of cannabis can
compensate for the drug's decremental effects by increased concentration
and by driving in such a way as to take fewer risks. To what extent they
can do this, however, is not clear. (pp. 118-119)

*The use of cannabis by narcotics addicts does not prove a causal
relationship between the use of cannabis and the use of heroin. What it
does show is that people who use one drug to excess may, and probably will,
use other drugs, and often they will use these drugs to excess also. (p. 121)

*The belief that cannabis causes crime emerged in the 1930's. ... It was
strengthened by propaganda, new penal legislation relating to cannabis, and
anecdotal reports of frenzied killings brought about by the drug. However,
every government sponsored commission of inquiry which has investigated the
relationship between cannabis and violent crimes has concluded that there
is no such connection. (p. 122)

*At present, it can be said that it is perfectly possible to use cannabis
in low doses intermittently without any lasting effects on the brain, and
that there is good evidence to suggest that chronic cannabis use is also
possible without brain damage. Thus the risk of brain damage from cannabis
use must be very small. (p. 123)

*[T]he amotivational syndrome appears to be more of a result of observer
bias than a real entity. ... Attempts to replicate the symptoms under
controlled conditions have been unsuccessful. It certainly does not occur
among chronic ganja smokers and careful studies of these groups have
indicated that many poor peasants use the drug to improve their work
capacity, and that they do indeed work more effectively while using the
drug. (p. 124)

*To date there is no evidence for an increased incidence in cannabis users
of those diseases that would be associated with a deficit in the cellular
immune mechanisms (e.g. viral infections or cancer). (p. 126)

Report of the National Task Force on Cannabis (Australia, 1994)

*While concern has been expressed at the possibility of marijuana
'flashbacks' resulting from the gradual release of stored THC and other
cannabinoids from fatty tissues into the bloodstream, the nature of the
metabolism of cannabinoids suggests that such a phenomenon is very
unlikely. Indeed, there is no evidence to suggest that the release of
cannabinoids stored in fatty tissues can produce noticeable subjective
psychoactive effects, or measurable impairment of psychomotor performance.
(p. 12)

*The acute toxicity of cannabis is very low, and there are no confirmed
cases of deaths from cannabis overdose in the world literature. (p. 13)

*It is difficult to estimate the magnitude of risk of being involved in
motor vehicle accidents due to cannabis intoxication. It is known that
cannabis intoxicated persons drive more slowly and take fewer risks than
alcohol intoxicated drivers. (p. 13)

*At present, there is no conclusive evidence that consumption of cannabis
by humans causes major impairments in immune functioning. (p. 14)

*Chronic heavy cannabis smoking may cause symptoms of chronic bronchitis,
such as coughing, sputum and wheezing. (p. 14)

*Concern has been raised by some case reports of cancers of the mouth,
throat and airways of young adults with a history of chronic heavy cannabis
smoking. Such studies are complicated by the presence of other risk factors
in these subjects, such as concurrent alcohol and tobacco use. However,
these reports highlight the need for further case-control studies of these
cancers to provide more definitive evidence. (pp. 14-15)

*It is uncertain whether its use during pregnancy causes a slightly
increased risk of birth defects, but until this issue is clarified, women
should be advised not to use cannabis during pregnancy. (p. 15)

*Although strong conclusions cannot be drawn, there is suggestive evidence
from some older American studies indicating that chronic heavy cannabis use
by adolescents may adversely affect their development. (p. 15)

*The evidence for the existence of an amotivational syndrome resulting from
chronic heavy cannabis use is equivocal; it is probable that, if it does
exist, it is a relatively rare occurrence, even among heavy, chronic
cannabis users. (p. 15)

*A cannabis dependence syndrome probably occurs in some chronic heavy users
of cannabis. Tolerance to some of the subjective and physiological effects
has been demonstrated, and some heavy users probably experience mild
withdrawal symptoms on abrupt cessation of use. (p.16)

*Long term heavy cannabis use does not appear to produce severe impairment
of cognitive function. (p. 16)

*There is no reliable evidence suggesting that chronic heavy cannabis use
leads to gross structural changes in the brain. This is consistent with the
evidence for only subtle cognitive effects from chronic cannabis use. (p. 16)

*THC has been shown to be an effective anti-emetic (anti-nausea) agent for
some patients undergoing cancer chemotherapy. (p. 17)

*There is reasonable evidence for the efficacy of THC in the treatment of
glaucoma, especially in cases which have proved resistant to existing
anti-glaucoma agents. (p. 17)

*There is suggestive evidence for the value of various cannabinoids as
anti-spasmodic and anti-convulsant agents. Further clinical research into
these applications is warranted, as well as into the potential value of
cannabinoids as analgesic and anti-asthma agents. (p. 17)

*There is need for further research into the effectiveness of cannabis and
its derivatives in assisting patients with HIV/AIDS related conditions, and
in particular, its value in counteracting weight loss associated with these
conditions, improving mood and easing pain. (p. 17)