Is cannabis use a risk to health?
A look at the evidence
Claims of various degrees
of harmfulness and danger associated with the smoking of cannabis are often cited
by prohibitionists and those who favour regulated legalisation alike.
see Pot Smokers Just As Healthy - Study: National Post (Canada), 11 June
2001
Whilst many people agree
that prohibition is unjust and ineffective, they differ in their opinions on
the needs for regulations. Whilst few would want unnecessary regulations and
limitations legislated onto cannabis once legal, few also would want to see no
regulations installed if indeed necessary. It is therefore vital that we
attempt to reach some sort of conclusion on the harm or potential harm through
individual or widespread cannabis use.
I have personally read many
reports from scientific and empirical studies on cannabis use, as well as some
of those based upon laboratory tests carried out on mice, rats, rabbits and
monkeys, using concentrated and synthetic THC - tetrahydrocannabinol - one of
the main active ingredients found in the parts of the cannabis plant used
recreationally and medically, particularly the tops and heads.
My own studies of the
evidence from both sides has led me to the following conclusions:
1) All of the allegations
of harm are based upon dubious work, laboratory experiments not involving
cannabis and not involving tests on humans, and unreliable anecdote often
exaggerated and g by drug workers.
2) Cannabis is indeed
"remarkably safe" and free from danger, barring of course the obvious
dangers of being hit over the head with a large lump of resin.
"We.. say that on the
medical evidence available, moderate indulgence in cannabis has little
ill-effect on health, and that decisions to ban or legalise cannabis should be
based on other considerations.": The Lancet, vol 352, number 9140,
November 14 1998
As it is nonsensical to
attempt to prove any substance to be completely harmless under all
circumstances, I am tackling this issue by listing the various harm allegations
and counteracting them with quotes from and references to the experts.
We must be careful to
distinguish the empirical evidence from studies of the health effects of herbal
and pure cannabis on people who smoke it and anecdotes or hypotheses base on
studies using chemical THC and other extracts on mice and monkeys in the
laboratory.
The Report of the World
Health Organisation, so often cited by those who claim cannabis to be a
health risk, says this:
"A great many assumptions have been made in extrapolating from
health effects observed in laboratory animals to the probable health effects of
equivalent doses and patterns of use in humans. In addition, there may be
problems in extrapolating studies with pure THC to human experience with crude
cannabis preparations. The plant material contains many other compounds, both
cannabinoid and non-cannabinoid in nature and the possibility must always be
considered that differences between experimental and clinical observations may
be due in part to the effects of these other substances."
Alun Buffry, BSc., Dip Com
(Open)
==========================
Myth: Cannabis is toxic
/ poisonous
DATED: SEP 6 1988
Findings of Fact:
"4. Nearly all
medicines have toxic, potentially lethal effects. But marijuana is not such a
substance. There is no record in the extensive medical literature describing a
proven, documented cannabis-induced fatality.
"5. This is a
remarkable statement. First, the record on marijuana encompasses 5,000 years of
human experience. Second, marijuana is now used daily by enormous numbers of
people throughout the world. Estimates suggest that from twenty million to
fifty million Americans routinely, albeit illegally, smoke marijuana without
the benefit of direct medical supervision. Yet, despite this long history of
use and the extraordinarily high numbers of social smokers, there are simply no
credible medical reports to suggest that consuming marijuana has caused a single
death.
"6. By contrast
aspirin, a commonly used, over-the-counter medicine, causes hundreds of deaths
each year.
"7. Drugs used in
medicine are routinely given what is called an LD-50. The LD-50 rating
indicates at what dosage fifty percent of test animals receiving a drug will
die as a result of drug induced toxicity. A number of researchers have
attempted to determine marijuana's LD-50 rating in test animals, without
success. Simply stated, researchers have been unable to give animals enough
marijuana to induce death.
"8. At present it is
estimated that marijuana's LD-50 is around 1:20,000 or 1:40,000. In layman
terms this means that in order to induce death a marijuana smoker would have to
consume 20,000 to 40,000 times as much marijuana as is contained in one
marijuana cigarette. NIDA-supplied marijuana cigarettes weigh approximately .9
grams. A smoker would theoretically have to consume nearly 1,500 pounds of
marijuana within about fifteen minutes to induce a lethal response.
"9. In practical
terms, marijuana cannot induce a lethal response as a result of drug-related
toxicity.
"10. Another common
medical way to determine drug safety is called the therapeutic ratio. This
ratio defines the difference between a therapeutically effective dose and a
dose which is capable of inducing adverse effects.
"11. A commonly used
over-the-counter product like aspirin has a therapeutic ratio of around 1:20.
Two aspirins are the recommended dose for adult patients. Twenty times this
dose, forty aspirins, may cause a lethal reaction in some patients, and will
almost certainly cause gross injury to the digestive system, including
extensive internal bleeding.
"12. The therapeutic
ratio for prescribed drugs is commonly around 1:10 or lower. Valium, a commonly
used prescriptive drug, may cause very serious biological damage if patients
use ten times the recommended (therapeutic) dose.
"13. There are, of
course, prescriptive drugs which have much lower therapeutic ratios. Many of
the drugs used to treat patients with cancer, glaucoma and multiple sclerosis
are highly toxic. The
therapeutic ratio of some
of the drugs used in antineoplastic therapies, for example, are regarded as
extremely toxic poisons with therapeutic ratios that may fall below 1:1.5. These
drugs also have very low LD-50 ratios and can result in toxic, even lethal
reactions, while being properly employed.
"14. By contrast,
marijuana's therapeutic ratio, like its LD-50, is impossible to quantify
because it is so high."
==
In the journal FUNDAMENTAL
AND APPLIED TOXICOLOGY, Dr. William Slikker, director of the Neurotoxicology
Division of the National Center for Toxicological Research (NCTR), described
the health of monkeys exposed to very high levels of cannabis for an extended
period:
"The general health of
the monkeys was not compromised by a year of marijuana exposure as indicated by
weight gain, carboxyhemoglobin and clinical chemistry/hematology values."
(TOXICOLOGY LETTERS, No
Increase in Carcinogen-DNA Adducts in the Lungs of Monkeys Exposed Chronically
to Marijuana Smoke, 1992, Dec;63 (3): 321-32.
THE ARKANSAS TIMES (Refer
Madness. 16 Sept 1993) asked Dr. Merle Paule of NCTR about evidence of cannabis
toxicity and the health of the monkeys in the study, Dr. Paule said,
"There's just nothing
there. They were all fine."
Myth: Cannabis
intoxicates
This is really a matter of
semantics, as, strictly speaking, a non-toxic substance cannot 'intoxicate'.
"intoxication" is
usually and often detectable simply by a detrimental effect upon motor and
cognitive skills; these are covered below.
Myth: Cannabis is
addictive
Here we must distinguish
between firstly, addictiveness and dependency, and secondly, between medical
and psychological dependency.
Medical dependency is not
really the issue here, since it is perfectly natural and acceptable for a
person to be dependent upon a medicine to ease their suffering, given that the
medicine is at least reasonably and acceptably safe.
TRENDS IN PHARMACOLOGICAL
SCIENCES: Neurobiology of Marijuana Abuse. 1992, 13:201-206. pg. 203:
"research shows
cannabis has limited potential for development of...psychological dependence
due to the weak reinforcing properties of Delta-9-THC."
BRAIN RESEARCH JOURNAL:
Chronic cannabinoid administration alters cannabinoid receptor binding in rat
brain: a quantitative autoradiographic study. 1993, 616:293-302. pg. 300.
"cannabinoid
dependence and withdrawal phenomena are minimal."
The Shafer Commission (USA)
of 1970 said:
"Marijuana does not
lead to physical dependency, although some evidence indicates that the heavy,
long-term users may develop a psychological dependence on the drug"
The Panama Canal Zone
Military Investigations (US Military, 1929) said:
"There is no evidence
that Marihuana as grown and used [in the Canal Zone] is a 'habit-forming'
drug."
In 1997, (R. v Clay),
Ontario Justice John McCart (Canada) ruled, "Cannabis is not an addictive
substance." B.C. Justice F.E. Howard in a similar case confirmed his
findings in 1998.
US Department of Health and
Human Services, 1991:
"Given the large
population of marijuana users and the infrequent reports of medical problems
from stopping use, tolerance and dependence are not major issue at
present."
("Drug Abuse and Drug
Abuse Research, Rockville, MD, (1991) p C3
Myth: Cannabis causes
hallucinations
Report of
the Australian Government, 1996: "Cannabis has been erroneously classified as a narcotic, as a
sedative and most recently as an hallucinogen. While the cannabinoids do
possess hallucinogenic properties, together with stimulant and sedative
effects, they in fact represent a unique pharmacological class of compounds.
Unlike many other drugs of abuse, cannabis acts upon specific receptors in the
brain and periphery. The discovery of the receptors and the naturally occurring
substances in the brain that bind to these receptors is of great importance, in
that it signifies an entirely new pathway system in the brain."
Myth: Cannabis causes
cancer
BOSTON, Jan. 30, 1997
(UPI):
"The U.S. federal
government has failed to make public its own 1994 study that undercuts its
position that marijuana is carcinogenic - a $2 million study by the National
Toxicology Program. The program's deputy director, John Bucher
(http://www.niehs.nih.gov/dirtob/bucher.htm), says the study "found
absolutely no evidence of cancer." In fact, animals that received THC had
fewer cancers. Bucher denies his agency had been pressured to shelve the
report, saying the delay in making it public was due to a personnel shortage.
CANCER PREVENTION DATA
"Marijuana Use and
Mortality": AMERICAN JOURNAL OF PUBLIC HEALTH, April 1997:
TABLE 2 Relative Risk of
Death for Ever Users and Current Users of Marijuana, by Sex and Cause of Death:
Kaiser Pemanente Medical Care Program Members (n = 65,171), Oakland and San
Francisco, June 1979 through December
1985 - section of table
regarding cancer (Neoplasms) as the cause of death:
MEN
Ever Users Relative Risk of
Cancer Death
Full Model 0.78
Non-smokers/ Occasional
Drinkers 0.46
Current Users
Full Model 0.97
Non-smokers/ Occasional
Drinkers 0.75
WOMEN
Ever Users
Full Model 0.82
Non-smokers/ Occasional
Drinkers 0.70
Current Users
Full Model 0.86
Non-smokers/ Occasional
Drinkers 0.56
Here, numbers less than one
for Relative Risk of Cancer Death represent a lower rate of fatal cancer among
marijuana smokers in the large Kaiser Study from California. For example, women
who are current marijuana smokers but did not smoke tobacco were found to have
only 56% of the risk of cancer death as compared to other women who were
non-smokers of both tobacco and marijuana.
Not only is the evidence
linking cannabis smoking to cancer negative, but the largest human studies
cited indicated that cannabis users had lower rates of cancer than nonusers.
What's more, those who smoked both cannabis and tobacco had lower rates of lung
cancer than those who smoked only tobacco-a strong indication of
chemoprevention. Even more, in 1975 researchers at the Medical College of
Virginia found that cannabis showed powerful antitumour activity against both
benign and malignant tumours (the government then banned all future
cannabis/cancer research).
(The Emperor Wears No
Cloths. Jack Herer, Queen of Clubs Pub, 1991)
(Ganja in Jamaica: A
Medical Anthropological Study of Chronic Marijuana Use. 1975. Anchor Books)
(Cannabis in Costa Rica: A
Study of Chronic Marijuana Use, 1980-82, Institute for the Study of Human
Issues, 3401 Science Center Philadelphia, PA.)
The NEW ENGLISH
DISPENSATORY of 1764 recommends boiled cannabis roots for the elimination of
tumours.(Marijuana: The First 12,000 Years. Plenum Press, 1980)
Powerful
evidence that cannabis not only does not cause cancer, but that it may prevent
and even cure cancer.<http://www.erowid.org/plants/cannabis/cannabis_health2.shtml>
SO, YOU THOUGHT IT WAS THE
TAR THAT CAUSED CANCER
Myth: Cannabis smoking
damages the lungs
Researchers at the
University of California (UCLA) School of Medicine have announced the results
of an 8 - year study into the effects of long-term cannabis smoking on the
lungs. In Volume 155 of the American Journal of Respiratory and Critical Care
Medicine, Dr. D.P. Tashkin reported "Findings from the present long-term,
follow-up study of heavy, habitual marijuana smokers argue against the concept
that continuing heavy use of marijuana is a significant risk factor for the
development of [chronic lung disease. ..Neither the continuing nor the
intermittent marijuana smokers exhibited any significantly different rates of
decline in [lung function]" as compared with those individuals who never
smoked marijuana. Researchers added: "No differences were noted between
even quite heavy marijuana smoking and non-smoking of marijuana."
Myth: Cannabis
suppresses the immune system. Two studies in 1978 and 1988 showed that cannabis actually
stimulated the immune system
From: "Exposing
Marijuana Myths:(The Lindesmith Center)" "False: Marijuana Impairs
Immune System Functioning "It has been widely claimed that marijuana substantially
increases users' risk of contracting various infectious diseases. First
emerging in the 1970s, this claim took on new significance in the 1980s,
following reports of marijuana use by people suffering from AIDS.
"THE FACTS
"The principal study fueling
the original claim of immune impairment involved preparations created with
white blood cells that had been removed from marijuana smokers and controls.
After exposing the cells to known immune activators, researchers reported a
lower rate of transformation in those taken from marijuana smokers.
"However, numerous
groups of scientists, using similar techniques, have failed to confirm this
original study. "In fact, a 1988 study demonstrated an increase in
responsiveness when white blood cells from marijuana smokers were exposed to
immunological activators.
"Studies involving
laboratory animals have shown immune impairment following administration of
THC, but only with the use of extremely high doses. For example, one study
demonstrated an increase in herpes infection in rodents given doses of 100
mg/kg/day -- a dose approximately 1000 times the dose necessary to produce a
psychoactive effect in humans.
"There have been no
clinical or epidemiological studies showing an increase in bacterial, viral, or
parasitic infection among human marijuana users. In three large field studies
conducted in the 1970s, in Jamaica, Costa Rica and Greece, researchers found no
differences in disease susceptibility between marijuana users and matched
controls.
"Marijuana use does
not increase the risk of HIV infection; nor does it increase the onset or
intensity of symptoms among AIDS patients. In fact, the FDA decision to approve
the use of Marinol (synthetic THC) for use in HIV-wasting syndrome relied upon
the absence of any immunopathology due to THC.
"Today, thousands of
people with AIDS are smoking marijuana daily to combat nausea and increase
appetite. There is no scientific basis for claims that this practice
compromises their immune responses. Indeed, the recent discovery of a
peripheral cannabinoid receptor associated with lymphatic tissue should
encourage aggressive exploration of THC's potential use as an immune-system
stimulant."
Marijuana Myths, Marijuana
Facts": Lynn Zimmer Ph.D. and John P. Morgan M.D.: "At the 1981
conference on marijuana sponsored by the World Health Organisation and Canada's
Addiction Research Foundation, reviewers of the research literature on immunity
reported "There is no conclusive evidence that cannabis predisposes man to
immune dysfunction". A few years late, in approving THC (Marinol) for use
as a medicine, the FDA found no convincing evidence that THC caused immune
impairment. In 1992, the FDA approved Marinol as an appetite stimulant
specifically for AIDS patients, who have serious immunosuppression."Marijuana
Myths, Marijuana Facts": Lynn Zimmer Ph.D. and John P. Morgan M.D. ISBN
0-9641568-4-9; page 107.Munson and Fehr (1983) note 15, page 338
Food and Drug
Administration, "Unimed's Marinol (Dronabinol) Lau, R.J. et al
"Phytohemagglutinin-Induced Lymphocyre Transformations in Humans Receiving
Delta-9-Tetrahydrocannabinol," Science 192, 805-07 (1976)Dax, EM. Et al.,
"The Effects of 9_ENE-Tetrahydrcannabinol on Hormone Release and Immune
Function," Journal of Steroid Biochemistry 34: 263-70 (1989)Myth: Cannabis
causes impotency / infertility
From: "Exposing
Marijuana Myths: (The Lindesmith Center)" page 93;"Studies of men in
the general population have also failed to find differences in the testosterone
levels of marijuana users and nonusers. "There is no convincing evidence
of infertility related to marijuana consumption in humans. "There are no
epidemiological studies showing that men who use marijuana have higher rates of
infertility than men who do not. Nor is there evidence of diminished
reproductive capacity among men in countries where marijuana use is
common."
Abel, E.L., et al,
"Marijuana and Sex: A Critical Survey," Drug and Alcohol Dependence
8: 1-22 (1981)
Ehrenkranz, J.R.L. and
Hembee, WC., "Effects of Marijuana on Male Reproductive Function,"
Psychiatric Annals 16: 243-49 (1986)
Cushman, P, "Plasma
Testosterone Levels in Healthy Male Marijuana Smokers," American Journal
of Drug and Alcohol Abuse 2: 269-75 (1975)
Block, R I, et al,
"Effects of Chronic Marijuana Use of Testosterone, Luteinizing Hormone,
Follicle Stimulating Hormone, Prolactin and Cortisol in Men and
women,"Drug and Alcohol Dependence 28,: 121-28 (1991)
Myth: Cannabis destroys
short-term memory
The
Australian Government Report 1996:
"The weight of the
available evidence suggests that the long-term heavy use of cannabis does not
produce any severe impairment of cognitive function."
Myth: Cannabis
detrimentally effects motor co-ordination / driving skill
Crancer Study, Washington
Department of Motor Vehicles:
"Simulated driving
scores for subjects experiencing a normal social 'high' and the same subjects
under control conditions are not significantly different. However, there are
significantly more errors for alcohol intoxicated than for control
subjects"
U.S. Department of
Transportation, National Highway Traffic Safety Administration (DOT HS 808 078), Final Report, November
1993:"THC's adverse effects on driving performance appear relatively
small"
Sutton (1983) also found
that cannabis had little effect on actual driving performance. "Driving in
traffic, however, while showing a trend toward poorer performance, was not
significantly affected, and the effects of cannabis were much more
variable."
The Australian Government
Report, 1996, page 6) "There is no controlled epidemiological evidence
that cannabis users are at increased risk of being involved in motor vehicle or
other accidents.
Myth: Cannabis
detrimentally effects cognitive skills
US: Cannabis Use and
Cognitive Decline in Persons under 65 Years of Age
Publication date: 1 May
1999
Source: American Journal of
Epidemiology
Copyright: 1999 Johns
Hopkins University School of Hygiene and Public Health
Ref: Am J Epidemiol 1999;
149:794-800
Mail: 111 Market Place,
Suite 840, Baltimore MD 21202 U.S.A.
<http://www.jhsph.edu/Publications/JEPI/"> Website
Authors: Constantine G.
Lyketsos, Elizabeth Garrett, Kung-Yee Liang, and James C. Anthony (Osler 320,
The Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD 21287-5371)
"The purpose of this
study was to investigate possible adverse effects of cannabis use on cognitive
decline after 12 years in persons under age 65 years. This was a follow-up
study of a probability sample of the adult household residents of East
Baltimore. The analyses included 1,318 participants in the Baltimore, Maryland,
portion of the Epidemiologic Catchment Area study who completed the Mini-Mental
State (MMSE) examination during three study waves in 1981, 1982, and
1993--1996.
Individual MMSE score
differences between waves 2 and 3 were calculated for each study participant.
After 12 years, study participants' scores declined a mean of 1.20 points on
the MMSE (standard deviation 1.90), with 66% having scores that declined by at
least one point.Significant numbers of scores declined by three points or more
(15% of participants in the 18--29 age group). There were no significant
differences in cognitive decline between heavy users, light users, and nonusers
of cannabis.
There were also no
male-female differences in cognitive decline in relation to cannabis use. The
authors conclude that over long time periods, in persons under age 65 years,
cognitive decline occurs in all age groups
This decline is closely
associated with ageing and educational level but does not appear to be
associated"
Ethiopian Zion Coptic
Church Study, 1980
"Some participants had
smoked at least two to four large cigarettes (each containing 1/4 to 1/2 ounce
of cannabis) over 16 hours a day for periods of up to 50 years.
"...the most
impressive thing... is the true paucity of neurological abnormalities.
"Heavy cannabis
consumers suffered no apparent psychological or physical harm. "Schaeffer:
A Neuropsychological Evaluation; A Case History"...I.Q.'s of Zion Coptics
increased after they began to use ganga"
US Jamaican Study 1974:
"No impairment of
physiological, sensory and perceptual performance, tests of concept formation,
abstracting ability, and cognitive style, and tests of memory"
Myth: Cannabis causes
a-motivation / laziness
We must of course
distinguish between those people who are naturally or by habit or psychological
so set as lazy or a-motivated, and any such a-motivation caused by cannabis
consumption.
Dr. Andrew Weil (Rubin
& Comitas Ganja in Jamaica, 1975) said "a-motivation [is] a cause of
heavy marijuana smoking rather than the reverse"
In 1997, (R. v Clay),
Ontario Justice John McCart (Canada) ruled, "Cannabis ... does not cause a
motivational syndrome." His findings were confirmed by B.C. Justice F.E.
Howard in a similar case in 1998
Myth: Cannabis use leads
to the use of hard drugs
Considering the millions of
people in the UK, and the hundreds of millions around the world, who have used
cannabis for short or long periods, it is clear that if it led to the use of
hard and addictive drugs there would be many more new addicts that we have
seen.
We must, here, also
remember that under the UK and other government policies of "tackling
drugs together", under a regime that prohibits hard drugs alongside
cannabis, where the supplies remain in criminal control, it is often the case
that people may be led from one substance to another by their peers and by
their suppliers. This does not of course mean that cannabis itself is a gateway
or hard drug use.
We must also remember that
at least a proportion of cannabis users may be people prone to trying other
substances, whether by way of n, research, 'spiritual' quest, or psychological
imbalance.
The
LaGuardia sub-committee of New York 1944 said:
"The use of marijuana
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 marijuana
smoking"
"Marijuana: Facts for
Teens." U.S. Department of Health and Human Services. Washington, D.C.
1995, p.10.: "Most marijuana users do not go on to use other drugs."
:
Jack Straw, The Daily
Telegraph, 3 April 2000: "While it is undoubtedly the case that many drug
addicts started with cannabis, to claim that taking cannabis is bound to lead
to hard drugs has always seemed to me far-fetched."
Drugs Policy in the Netherlands
(1995): Dutch Ministry of
Health, Welfare and Sport "Moreover, users of soft drugs do not as a rule
tend to experiment with hard drugs, such as heroin or cocaine; this is indeed
the intention of the policy of keeping the markets separate. There is little
use of heroin and cocaine among minors in the Netherlands, and the trend is
towards even less. "Myth: Increased availability will lead to increased
usage"
Drugs Policy in the
Netherlands (1995): Dutch Ministry of Health, Welfare and Sport"4.1.
Extent and nature of cannabis use
"The decriminalisation
of the possession of soft drugs in 1976 did not result in increased use. The
level of consumption stabilised in the first few years after the Opium Act was
amended. According to national figures, use again increased somewhat between
1984 and 1994, a trend which has also been observed elsewhere. Indeed, the
United States has experienced a considerable increase in recent years.
"Both as regards the extent of cannabis use and trends in use, the
Netherlands differs very little from other countries.
"As already indicated,
the number of users of soft drugs has increased after falling in the 1970s.
Patterns of consumption are overwhelmingly recreational, though among certain
specific categories of young people, such as chronic truants and street
children, the use of cannabis can be described as very substantial and
intensive.
"The policy pursued by
the Netherlands does not appear to have led to an increase in use, though there
are indications that the existence of freely accessible coffee shops means that
certain users continue to use the drugs for longer.
"Conclusions and
policy intentions
"The decriminalisation
of the possession of quantities of soft drugs for personal use and the
existence of sales points tolerated under certain circumstances by the
authorities have not resulted in a worryingly high level of consumption among
young people. Moreover, users of soft drugs do not as a rule tend to experiment
with hard drugs, such as heroin or cocaine; this is indeed the intention of the
policy of keeping the markets separate. There is little use of heroin and
cocaine among minors in the Netherlands, and the trend is towards even less.
"The effects of
partial decriminalisation on cannabis use in South Australia, 1985 to 1993
National Drug and Alcohol Research Centre, University of New South Wales,
Sydney Aust J Public Health, 19: 3, 1995 Jun, 281-7:"
In 1987 the Cannabis
Expiration Notice scheme decreased penalties for the personal use of cannabis
in South Australia. Data from four National Campaign Against Drug Abuse (NCADA)
household drug-use surveys covering the period 1985 to 1993 were analysed to
measure the effect of the decriminalisation on cannabis use. The main outcomes
used were the self-reported prevalence rates of having ever used cannabis and
current weekly use. Logistic regression was used to control for the potentially
confounding effects of age and sex. Other outcomes were rates of having ever
been offered cannabis and willingness to use cannabis if offered it. Between
1985 and 1993 the adjusted prevalence rate of ever having used cannabis
increased in South Australia from 26 per cent to 38 per cent. There were also
significant increases in Victoria and Tasmania, and to a lesser extent in New
South Wales. The increase in South Australia was not significantly greater than
the average increase (P = 0.1). Adjusted rates of weekly use increased between
1988 and 1991 in South Australia, but did not change through 1993. Although the
effect was in the direction of a greater increase in South Australia, this was
not statistically significant when compared to increases in the rest of
Australia (P = 0.07). The greatest increase in adjusted weekly use occurred in
Tasmania between 1991 and 1993, from 2 per cent to 7 per cent. Although the
NCADA survey data indicate that there were increases in cannabis use in South
Australia in 1985-1993, they cannot be attributed to the effects of partial
decriminalisation, because similar increases occurred in other states"
And now, some general
quotes on the health effects of smoking cannabis:
March 20, 1997, Sydney,
Australia: The National Drug and Alcohol Research Centre in Australia. The
study, which involved interviews with 268 marijuana smokers and 31 non-using
partners and family members, is one of the first ever conducted in Australia to
determine the effects of long-term marijuana use. Its findings were reported by
the Sydney Morning Herald last month. "We don't see evidence of high
psychological disturbance among the [long- term users,]" said chief
investigator David Reilly. "The results seem unremarkable; the exceptional
thing is that the respondents are unexceptional. "The Report of the
Australian Government 1996 says: "The ... major possible adverse effects
of chronic, heavy cannabis use ... remain to be confirmed"
"The major health and
psychological effects of chronic cannabis use, especially daily use over many
years, remain uncertain"
"As has been stressed
... there is uncertainty. ......To varying degrees....inferences from animal
research, laboratory studies, and clinical observations about probable ill
effects. In some cases inferences depend upon arguments from what is known
about the adverse effects of other drugs, such as tobacco and alcohol".
"The probable and
possible adverse health and psychological effects of cannabis need to be placed
in comparative perspective to be fully appreciated".
The USA Merck Manual of Diagnosis
and Therapy (1987) says:
"Cannabis can be used
on an episodic but continual basis without evidence of social or psychic
dysfunction. In many users the term dependence with its obvious connotations,
probably is mis-applied... The chief opposition to the drug rests on a moral
and political, and not toxicologic, foundation".
Jamaican Study 1970
:"... as a multipurpose plant, ganga is used medicinally, even by
non-smokers. ....There were no indications of organic brain damage or
chromosome damage among smokers and no significant clinical psychiatric,
psychological or medical) differences between smokers and controls."
UK
Royal Commission, The Wootton Report, UK, 1968: "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 (1893-94) and the New York Mayor's
Committee (1944 - LaGuardia) that the long-term consumption of
cannabis in moderate doses has no harmful effects"
LaGuardia
Commission Report,
1944" Cannabis smoking] does not lead directly to mental or physical
deterioration... Those who have consumed marijuana for a period of years showed
no mental or physical deterioration which may be attributed to the drug"
Panama Canal Zone Report,
1925"
There is no evidence...
that any deleterious influence on the individual using [cannabis]"
Indian
Hemp Drugs Commission,
1894
"The commission has
come to the conclusion that the moderate use of hemp drugs is practically
attended by no evil results at all. ... ...moderate use of hemp... appears to
cause no appreciable physical injury of any kind,... no injurious effects on
the mind... [and] no moral injury whatever."
see also: