CHAPTER 6 RECREATIONAL USE
OF CANNABIS
Prevalence
6.1 Cannabis is by
far the most widely used illicit drug in the United Kingdom, as
in most other Western countries; and almost all of this use is
for recreational rather than medical purposes. According to the
Department of Health, "Cannabis is now the third most commonly
consumed drug after alcohol and tobacco" (p 47).
6.2 Cannabis dominates
the drug crime statistics, and the figures are rising. Figures
for the whole United Kingdom for 1996 (Home Office Statistical
Bulletin 10/98) show that 72,745 drug offenders (77 per
cent of the total) committed offences involving cannabis (alone
or with other drugs). There were 91,432 seizures of cannabis in
1996 (75 per cent of the total for all drugs) and this involved
record quantities of cannabis resin (66,921 kg), herbal cannabis
(34,373.6 kg) and cannabis plants (116,119 plants). These
figures, which are the most recent available, represent more than
a threefold increase over 1990, with a particularly sharp
increase in the number of offences related to the cultivation
of cannabis plants and the numbers of plants seized.
6.3 It is difficult
to put a figure on the prevalence of cannabis use in the United
Kingdom. The Parliamentary Office of Science and Technology, in
their Cannabis Update of March 1998, gave figures from
the British Crime Survey 1994 which indicate that in the adult
population (16-59) 1 in 5 had "ever tried"
cannabis (1 in 20 within the previous month) and in the 1629
age group just over 1 in 3 had "ever tried"
cannabis (1 in 20 within the previous month). These figures are
not dissimilar to those in the WHO report for other countries
in Europe[23],
with somewhat higher figures for the USA, Canada and Australia.
They suggest that as many as 7.5m people aged 16-59 in the United
Kingdom have used cannabis at least once, and that between 1.5m
and 2m take the drug at least once a month (cp Montgomery Q 559).
The Royal College of Physicians have established a Joint Working
Party with the Royal College of Psychiatrists which among other
matters will review the epidemiology of illicit drug use in the
United Kingdom.
Pattern
of use
6.4 The pattern of
cannabis consumption in the United Kingdom varies according to
geography, socioeconomic conditions and the age of the user.
Professor Edwards observed that cannabis is and has been
used in very different ways in different times and places; for
instance, there are people in south London who smoke 20 joints
a day (Q 26). Dr Robson cautions that much of the use
of cannabis in the community does not come to the attention of
the health services or the police, and therefore little is known
about it (Q 456).
6.5 The Independent
Drug Monitoring Unit conducted a survey of 1,333 regular cannabis
users who attended a major pop festival in Britain in the summer
of 1994 (p 231). The majority were daily cannabis users with
an average consumption of about 24.8g of cannabis resin per month.
Respondents gave highly positive subjective ratings to cannabis
(as opposed to negative subjective ratings to solvents, cocaine
and heroin). More than 60 per cent believed that cannabis
had been of benefit to their physical or mental health. They would
prefer that the law was more liberal, but a majority (70 per
cent) did not think that they would use more if it was.
6.6 Dr James Robertson,
a GP working in Edinburgh, has reported the results of a survey
(funded by the Royal College of General Practitioners) of 328
consecutive patients attending his surgery (average age 33.7 years)[24].
200 patients (61 per cent) said that they had used cannabis
at least once, and more detailed interviews of 101 of these revealed
that 90 were regular users, with 67 using cannabis on a daily
basis. Most spent £25 or less per week on cannabis, but a
small number of individuals spent £100 or more per week.
6.7 Neil Montgomery
described for us various ways to take cannabis recreationally
(QQ 544-554). He divides recreational users into three groups:
·
Casual Irregular use, in amounts up to 1g of resin
at a time, to an annual total of no more than 28g (Q 545);
·
Regular Regular use, typically of 0.5g of resin a day
(equivalent to 3 or 4 smokes of a joint or pipe), adding up to
about 3.5g per week (Q 548);
·
Heavy More or less permanently stoned, using more
than 3.5g of resin per day and 28g or more per week (Q 554).
The smallest group, around 5 per cent. "The extent to
which a heavy user can consume cannabis is largely unappreciated."
Herbal cannabis appears to be consumed
at twice the rate of cannabis resin, presumably because of its
lower content of THC. Comparable data are provided by IDMU (pp
2313).
6.8 According to POST's
Cannabis Update, 9 per cent of ever-users use cannabis
daily, and 14 per cent several times a week, making it of
all illegal drugs the one most likely to be used regularly. According
to Professor John Strang, Director of the National Addiction
Centre, few users end up in hospital with acute psychiatric problems,
and most regular users are not nowadays advised by their doctor
to change their habits (Q 244). For the risk of dependence,
see Chapter 4.
6.9 Many cannabis users
also consume a variety of other psychoactive agents. As the commonest
method of using cannabis in the United Kingdom is to smoke cannabis
resin mixed with tobacco, nicotine use is very high among cannabis
users. Among other things, this makes it difficult to assess the
respiratory risks of smoked cannabis as they are confused with
the well-established risks of smoked tobacco. Alcohol use is also
common, but regular cannabis users may consume less than non-cannabis
users. Drug treatment clinics often see poly-drug users, who are
consuming a variety of illicit substances, of which cannabis is
commonly one (QQ 42, 216, 487, 515, 562; DH p 47).
6.10 According to the
Department of Health, most cannabis users have discontinued by
their mid to late 20s (p 46); and of those who have ever
been daily users, only 15 per cent persist with daily use
in their late 20s (p 45). Neil Montgomery has identified
a group of regular users who stop in their 30s and start again
in their 50s (Q 575).
Content
of cannabis consumed in the United Kingdom
6.11 Some of our witnesses
expressed concern that the preparations of illicit cannabis used
in the United Kingdom today are more potent than previously, exposing
users to a greater risk of acute intoxication and long-term adverse
effects. Professor Ashton (p 12) suggested that "a typical
1970s `reefer' contained about 10 mg of THC..., while a typical
`joint' today may contain 60-150 mg or more of THC. This increase
in potency results from sophisticated plant breeding and cultivation
methods leading to highly potent varieties of cannabis, such as
Skunkweed". Other witnesses made similar assertions (e.g.
Q 33).
6.12 However, the Home
Office Forensic Science Service, who have data on the THC content
of seized cannabis samples, do not support the view that most
users in the United Kingdom are exposed to material containing
ten times as much THC as in the 1960s and 1970s. They say, "Cannabis
resin...has a mean THC content of 4-5 per cent, although
the range is from less than 1 per cent to around 10 per cent.
This pattern has remained unchanged for many years" (p 218).
Cannabis resin, imported most commonly from Morocco, Afghanistan
or Pakistan (IDMU p 230), is the form of cannabis most widely
used in the United Kingdom, and accounted for two thirds by weight
of all seized material in 1996 (Home Office Statistical Bulletin
10/98). One of our witnesses, a user and convicted dealer, claimed
that most modern cannabis is in fact weaker than material from
the 1960s.
6.13 On the other hand,
there appears to have been an increase in the THC content of herbal
cannabisprobably because of the use of new strains of cannabis
plant and improved growing conditions. In the United States, the
University of Mississippi have analysed the THC content of seized
cannabis on behalf of the US government since 1980 (see Appendix
4, paragraph 13). They report an increase in the THC content of
herbal cannabis from around 2 per cent in 1980-81 to more
than 4 per cent in 1997. The Forensic Science Service report
that herbal cannabis in the United Kingdom currently also contains
an average of 4-5 per cent THC. They also report that cannabis
grown in the home, using improved growing techniques and improved
plant varieties, now produces herbal cannabis with a considerably
higher THC content, with an average close to 10 per cent
THC and a range extending to over 20 per cent (p 218).
Use of "hydroponic" cannabis (grown in a nutrient solution
rather than in soil) appears to be increasing rapidly, with plant
seizures in the United Kingdom up from 11,839 plants in 1992 to
116,119 in 1996.
6.14 Professor Hall
suggested, "More potent forms of cannabis need not inevitably
have more adverse effects on users' health than less potent forms.
Indeed, it is conceivable that increased potency may have little
or no adverse effect if users are able to titrate their dose to
achieve the desired state of intoxication. If users do titrate
their dose, the use of more potent cannabis products would reduce
the amounts of cannabis material that was smoked, thereby marginally
reducing the respiratory risks of cannabis smoking" (p 221;
cp IDMU p 235).
6.15 The overall quality
of imported cannabis resin appears to have fallen in recent years;
many users perceive cannabis resin as adulterated and forensic
analysis frequently confirms that this is the case, with the addition
of caryophyllene, a constituent of cloves, being particularly
common (IDMU p 230; Montgomery p 132 and QQ 577, 589).
Yet Professor Hall considers that concern about herbicide contamination
is unfounded, and that case history evidence of health problems
from microbial contamination is limited. Neil Montgomery
calls for research in this area.
The
state of the law
6.16 This Government
show no sign of taking a softer line against recreational use
of cannabis than their predecessors. According to the White Paper
Tackling Drugs (Cm 3945) of April 1998, "The
more evidence that becomes available about the risks of, for example,
cannabis...the more discredited the notion that any of the substances
currently controlled under the 1971 Act are harmless". This
echoes the view of Professor Edwards of the ACMD: "We are
in a rapidly changing field of knowledge"; and new knowledge
is making cannabis look more dangerous, not less (QQ 21,
27).
6.17 Most of our professional
witnesses agree that the adverse effects of cannabis fully justify
prohibition (e.g. Henry/RCPath p 224). The only argument
on the other side is that cannabis is arguably less dangerous
than alcohol or tobacco (e.g. RCGP p 281, Kendall p 268).
Professor Hall acknowledged this, but noted "the difficulty
in predicting the effect that relaxation of cannabis prohibition
would have on current patterns of cannabis use and the harms caused
by that use" (p 222).
6.18 The Under-Secretary
of State at the Home Office, George Howarth MP, told us confidently
that legalising recreational use would cause such use to increase
(Q 674). Professor Edwards, writing for the Royal Society,
is less sure: "We would expect weakening of controls over
cannabis to result in increased use levels, but this is an empirical
question on which research at present is not conclusive...Removal
of prohibition on cannabis would have to be described as a voyage
into the unknown. Some added harm and some added costs would undoubtedly
result" (p 303). There is international experience which
might throw light on this question, but we have not explored it
in detail.
6.19 We have not considered
the wider range of social and criminological issues which would
be raised by any proposal to change the law on recreational cannabis
use. These include enforcement, the impact on use of other illegal
drugs, and the international context and the danger of "drug
tourism"; as well as ethical, philosophical and religious
questions about the freedom of the individual, the nature of society
and the morality of mind-altering drugs. As we said when we began
this enquiry, these matters fall outside our remit as a Science
and Technology Committee. An Independent Inquiry into the Misuse
of Drugs Act, chaired by Lady Runciman of Doxford and supported
by the Police Foundation, is currently considering the matter
in its wider context; they expect to report next year.
23 See also the Annual Report on the State of the
Drugs Problem in the EU 1997, by the European Monitoring Centre
for Drugs and Drug Addiction. Back
24
Br. J. Gen. Pract. 1996, 46, 671. Back
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