http://bmj.com/cgi/content/full/324/7329/105?lookupType=volpage&vol=324&fp=105&view=short
BMJ 2002;324:105-108 ( 12 January
)
Education and debate
Alex Wodak and colleagues argue that the costs - to health, and fiscal and social - of controlling cannabis are greater than any benefits. In opposition, Colin Drummond lists the potential dangers of decriminalisation.
For
Alex Wodak, director, (a) Craig Reinarman,
professor, (b) Peter D A Cohen, director. (c)
(a) Alcohol and Drug Service, St
Vincent's Hospital, Darlinghurst, NSW 2010, Australia,
Current debates on cannabis policy
are dominated by attempts to establish the potential health costs of use
of cannabis.(1) While accurate assessment of the potential harms of cannabis
is desirable, it is at least as important to estimate the costs - which
are usually ignored - of current cannabis controls.
High costs of control noted decades
ago
Perhaps doctors have often led the
search for less harmful drug policies because the premier axiom of medicine
is "first, do no harm." In 1893 Britain's Indian Hemp Drugs Commission
concluded that excessive use of cannabis was uncommon and that moderate
use produced practically no ill effects. In 1926, Sir Humphrey Rolleston,
then president of the Royal College of Physicians, chaired a committee
that recommended against criminalising opiates.(2) Similarly, Dr W C Woodward,
counsel to the American Medical Association, testified in Congress in 1937
to the lack of evidence justifying criminalisation of cannabis(3) and several
other commissions in Britain, Canada, and the United States have come to
similar conclusions.(4) In 1972, an American presidential commission concluded
that marijuana "does not warrant" the harmful consequences of "criminal
stigma and threat of incarceration."(5) In 1978, President Carter told
Congress that "penalties against the use of a drug should not be more damaging
to an individual than the use of a drug itself; and where they are they
should be changed. Nowhere is this more clear than in the laws against
the possession of marijuana."(6) Unfortunately, little has changed since
President Carter uttered these words. The UK Police Foundation's review
of cannabis policy in 2000 was the most recent senior international committee
to reach the same verdict: "Our conclusion is that the present law on cannabis
produces more harm than it prevents."(7)
Social costs
Beyond the substantial fiscal costs
of enforcing the prohibition of cannabis, the social costs of such policies
are considerable. Around the world each year, the lives, education, and
careers of hundreds of thousands of people are damaged by the stigmatising
experience of arrest. Families face lost incomes and emotional stress.
Many cannabis users are already socially disadvantaged, so for them criminal
penalties for possession of cannabis often entail additional costs, including
disruption of relationships and loss of housing and employment.(8) Current
cannabis controls drive a wedge between parents and their children, health
professionals and their patients, teachers and their students, and police
and their communities. It is impossible for the many young people who use
cannabis today to obtain reliable information about the concentration of
psychoactive ingredients or the purity of samples they purchase, or even
about less harmful ways of using the drug. Consequently, current cannabis
policies are inimical to desirable public health outcomes.
Other serious costs are borne by
communities. Despite its criminalisation, the use of cannabis has become
so normalised that it is seen throughout most Western nations. Prohibition
in the face of strong and consistent demand inevitably results in supplies
being provided from illegal sources. The unregulated black market brings
consumers of cannabis into direct contact with sellers of other illicit
drugs. For example, in identical surveys of random samples of experienced
marijuana users, 55% of respondents in San Francisco reported that they
could buy other illicit drugs where they bought cannabis. In Amsterdam,
where cannabis sales are regulated and rarely attract criminal sanctions,
only 17% could get other illicit drugs from their source of cannabis.(9)
Allocating police to enforce the laws against cannabis reduces resources
available to enforce laws against more serious crimes. The riches available
in black markets increase the risk of serious corruption. During the last
decade, royal commissions in two Australian jurisdictions concluded that
police corruption was rampant and linked to drug prohibition.(10)
Liberalising control does not
increase use
The justification for cannabis prohibition
is that it is supposed to reduce demand and supply, thereby reducing use
and thus overall adverse health consequences. But demand, supply, and use
have all varied widely over time, quite irrespective of controls. Evidence
suggests that use is not increased by less intensive control. In the 11
American states that effectively decriminalised cannabis use in the 1970s,
use has not risen beyond that experienced by comparable states in which
it is prohibited.(11) Similarly, the Netherlands for all intents and purposes
decriminalised cannabis 25 years ago, but the prevalence there has remained
roughly parallel to that in Germany and France and well below that in the
United States.(12)
The major barriers to reconsideration
of the punitive prohibition of cannabis are political, not scientific or
legal
There is an increasingly widespread
view that international attempts to control cannabis by prohibiting its
use have failed and cannot be remedied. Numerous professional associations
in medicine, public health, law, and criminology have recognised this failure
and the enormous collateral costs of prohibiting cannabis and have recommended
consideration of less harmful regulatory alternatives.(13) The Single Convention
(1961), the treaty providing the major legal framework for international
prohibition of cannabis, states that "a party [government] shall, if in
its opinion the prevailing conditions in its country render it the most
appropriate means of protecting the public health and welfare, prohibit
[the use of cannabis]."(14) Where is the compelling evidence that protection
of public health and welfare is "most appropriately" served by the present
laws on cannabis? Regulation of cannabis would not breach any nation's
international treaty obligations. The major barriers to reconsideration
of the punitive prohibition of cannabis are political, not scientific or
legal.
The belief that more intensive
law enforcement will achieve better public health outcomes represents a
triumph of hope over experience
All drugs have risks. Cannabis is
not harmless, but adverse health consequences for the vast majority of
users are modest, especially when compared with those of alcohol or tobacco.
Attempts to restrict availability of cannabis by more intensive law enforcement
have been expensive, ineffective, and usually counter productive. The belief
that more intensive law enforcement will achieve better public health outcomes
represents a triumph of hope over experience. If we discovered that a drug
we had been using failed to relieve patients' symptoms and produced unpleasant
side effects, would any of us increase the dose?
It is time to acknowledge that the
social, economic, and moral costs of cannabis control far exceed the health
costs of cannabis use. The search should begin for more effective means
to reduce the harms that can result both from cannabis and from our attempts
to control it.
- Alex Wodak, Craig Reinarman, Peter
Cohen
Footnotes
Competing interests: None declared.
References
1. Strang J, Witton J, Hall
W. Improving the quality of the cannabis debate: defining the different
domains. BMJ 2000; 320: 108-110[Full Text].
Against
Colin Drummond, reader in addiction
psychiatry.
Department of Addictive Behaviour
and Psychological Medicine, St George's Hospital Medical School, London
SW17 0RE
Proponents of legalisation would
have you believe that it is a harmless form of recreational pleasure. It
is used mainly by responsible adults and the government has no place in
interfering. Penalties for possession and use are disproportionate to the
threat posed to the individual user or to society. Very few are harmed
by its use: only a reckless minority gives responsible users a bad name
by association. Besides, criminalisation fuels rather than prevents an
illegal trade and fails to stamp out availability.
The above refers not to cannabis,
but to handguns. The United Kingdom's already strict pre-1996 firearms
laws did not protect the innocent from the 1996 Dunblane tragedy, though
on a wave of popular support from the media the UK government afterwards
rapidly almost completely outlawed possession and use of handguns. Now
the pro-cannabis legalisation lobby, supported by the same parts of the
media that were outraged by Dunblane, seeks to legalise cannabis.
Health risks of cannabis
The pro-cannabis lobby conveniently
overlooks the serious health effects of cannabis, pointing to its safety
record in comparison with other illicit and legal drugs, such as tobacco
and alcohol. The lobby would have us believe that cannabis never killed
anyone. It is true that cannabis is relatively safe in overdose compared
with heroin, but it is far from harmless in the longer term, particularly
for heavy or regular users. The World Health Organization has concluded
that cannabis, when smoked, is twice as carcinogenic as tobacco.(1) It
causes carcinoma of the lungs, larynx, mouth, and oesophagus as well as
other chronic pulmonary diseases,(2) with evidence of a dose-response relation.(3)
These carcinomas appear earlier than cancers that are purely the result
of tobacco smoking. Cannabis increases the risk of death in people with
heart disease.(4) Furthermore, cannabis is now 10 times as pure as it was
20 years ago, which points to potentially greater health risks than earlier
research has identified.(5)
In vulnerable individuals, cannabis
precipitates schizophrenia and other psychotic disorders and worsens their
course. (2, 6) It is worth remembering that about 15% of schizophrenic
patients commit suicide. This is not to mention other clear adverse psychological
effects of cannabis, including depression, anxiety, and violent behaviour.(6)
Cannabis has up to 60 psychoactive ingredients, so it is hardly surprising
that it is bad for the mental health of many vulnerable people.
Apart from death, cannabis also causes
dependence in about 10% of users and in 50-90% of regular users.(2) The
number of cannabis users seeking specialist help has doubled in the past
10 years, accounting for 10% of attendances at drug treatment clinics in
the United Kingdom.(7) This is likely to be an under-representation, as
most clinics tend to be geared more towards helping users of opiates. Also
included among the risks are impairment of cognitive function, reduced
academic achievement, teratogenic effects, immunosuppression, impaired
fertility, and increased promiscuity and sexually transmitted diseases
in regular users. (2, 5, 6, 8) As Henry has recently pointed out "it is
perilous for the voice of science to be drowned out by campaigners for
legalisation who are dismissive of the mounting evidence on dependence
and harm."(9)
The effect of cannabis intoxication
on cognitive and motor functions is another aspect of the harm it does.
Research on the adverse effects of cannabis in vehicle accidents is complicated
by confounding factors such as alcohol intoxication, although in one UK
study of fatal road accidents, no alcohol was detected in the bodies of
80% of people found positive for cannabis at necropsy.(10) It is now recognised
that the separate effects of alcohol and cannabis on psychomotor impairment
and driving performance are approximately additive.(2) And yet because
of the absence of a roadside test equivalent to the breathalyser for alcohol,
cannabis is much more difficult for the police to detect accurately. All
of this points to appreciable social, health, and economic hazards of cannabis.
So called benefits of legalisation
The pro-legalisation lobby claims
potential benefits of legalisation in terms of curtailing the black market.
But even in Holland, where cannabis has been quasi-decriminalised, some
two thirds of the supply of cannabis takes place outside the regulated
"coffee shop market."(8) Further, with 1/8 ounce of cannabis costing on
average as little as £5 in the United Kingdom,8 it would be difficult
if not impossible for a legal, regulated, and taxed market to undercut
the illegal drugs pushers. Just the same problems attend the growing illicit
trade in "bootleg" alcohol and tobacco imported from mainland Europe to
Britain, bypassing any regulation of sale, particularly of sale to vulnerable
children.
The pro-cannabis lobby conveniently
overlooks the serious health effects of cannabis
Even the much vaunted advantages
of cannabis for medical purposes have yet to be proved: so far the evidence
suggests that cannabis has more adverse effects than do existing recognised
treatments. (11, 12) If it does emerge that cannabinoids are efficacious
in certain medical conditions, their licensing as medicines does not require
any legal action and is a completely different matter from legalisation
of recreational use of cannabis.
In any case, comparison with licit
drugs such as tobacco and alcohol hardly provides a model for legalisation.
Alcohol claims in excess of 40 000 lives a year in Britain(13) and tobacco
some 120 000.(14) No similar estimate is available for cannabis, and no
one knows what would be the final toll from its legalisation.
Is deregulation practicable?
The cannabis "industry" is big business,
accounting for a reported £4000m turnover a year. The recent share
flotation of GM Pharmaceuticals, which manufactures cannabinoids for medical
purposes, raised £25m and was six times oversubscribed. With legalisation,
it would not be long before the discredited tobacco industry would find
new markets for cannabis products. This same tobacco industrywhich is roundly
criticised for marketing a killer product and for its lack of ethics and
its cynical exploitation of the vulnerability of the addicted public by
concealment of the health risksis hounded by the same press that now advocates
legalisation of cannabis.
The pro-cannabis lobby would have
us believe that a legal cannabis market could be successfully regulated
by the UK government, when successive governments have for years failed
to act decisively against the tobacco industry and are still failing to
deal effectively with the alcohol industry. Two years on, we still await
the government's response to Alcohol Concern's proposals for a national
alcohol strategy.
The evidence base of the harms caused
by cannabis is undoubtedly incomplete and the evidence in some cases is
conflicting and confounded, but legalisation of cannabis would, on the
basis of what we currently know, lead to increased use and increased harm
to public health. As was the case with our old gun laws, no amount of regulation
of a legal market would protect vulnerable individuals such as children
and mentally ill people.
What we need instead is better public
education on the true risks of cannabis and greater availability of treatment
for people who are addicted. If there is to be any change in the law in
relation to cannabis it should be in terms of the way the law is enforced,
including greater consistency throughout the country, and a review of the
penalties for possession, rather than any change in the statutes or any
departure from international drug conventions. There should be greater
emphasis on helping people experiencing problems with cannabis to obtain
appropriate treatment.
Perhaps only a minority would be
killed or injured by the legalisation of cannabis. But this would be of
no comfort to you if your son or daughter was killed by a drug driver or
sectioned into psychiatric hospital with a drug induced psychosis. The
UK home secretary, David Blunkett, would be well advised to consider more
fully the health risks of cannabis before proceeding with his decriminalisation
proposal. Reducing police and court time through decriminalisation is likely
to be at the expense of public health.Colin Drummond
Footnotes
Competing interests: None declared.
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© BMJ 2002
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(c) Center for Drug Research, University
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