| Khat (Qat): Assessment of Risk to the Individual and Communities in
the UK.
Executive summary
1.
Introduction
1.1 Khat
is a herbal product consisting of the leaves and shoots of the shrub Catha edulis. It is cultivated in the Horn of Africa and the
Arabian Peninsula and chewed to obtain a stimulant effect.
1.2 Khat
is not currently controlled under the Misuse of Drugs Act 1971. Two
of the chemical constituents isolated when the plant is chewed,
cathinone and cathine, are classified as Class C drugs under the
Act.
1.3 This
report considers the necessity of inclusion of khat under the Misuse
of Drugs Act based on its harmfulness or other legislative changes
that may be appropriate.
1.4 The
report is based on a detailed scrutiny of the relevant scientific
literature. It considers the current level of khat use in the UK,
the health risks from using khat, and the harms to society as a
consequence of khat use.
2.
Background
2.1 In
February 2005 the Minister responsible for Drugs asked the Advisory
Council on the Misuse of Drugs (ACMD) to advise the government as to
the current situation in the UK and the risks associated with khat
use. This report is the basis of the Khat Working Group’s advice to
the ACMD. 2.2 The
ACMD is established under the 1971 Misuse of Drugs Act to keep under
review the drug situation in the United Kingdom and to advise
government ministers on measures to be taken for preventing the
misuse of drugs or for dealing with the social problems connected
with their misuse.
2.3 The
classification of drugs, in Schedule 2 of the 1971 Misuse of Drugs
Act, is based on the harm they cause:-
Class
A: (most
harmful) includes cocaine and heroin. Class
B: (intermediate category) includes amphetamines and barbiturates. Class
C: (least
harmful) includes cannabis, anabolic steroids and benzodiazepines.
2.4 When
advising about harm the ACMD takes account of the physical harm they
may cause, their pleasurable effects, any associated withdrawal
reactions after chronic use, and the harm that misuse may bring to
families and society at large. 3.
Epidemiology
3.1
Information about the use of khat in the UK comes from reports into
the communities from countries that traditionally use khat. Such
reports are subject to sampling bias due the way interviewees are
recruited. The largest epidemiological survey of drug misuse in
England and Wales, the British Crime Survey, does not include khat
as one of its reference drugs.
3.2 Most
of the prevalence data comes from the Somali community. Figures
range from 34% to 67% of the Somali community who identify
themselves as current users of khat. The figure of 34% is from the
highest power study and likely to be the most accurate figure. The
wide range is due to the sampling techniques employed, males tend to
report more use than females, so if the group sampled is biased
toward men, the prevalence increases.
3.3
There are no published reports in the other individual ethnic
communities. When ethnic communities are grouped together people
reporting current khat use ranges between 37% and 60%.
3.4
Levels of khat use in traditional khat chewing countries are
comparable if not slightly higher, than rates in the UK. In Somalia
a large survey found 31% of respondents admitting current use. In
Ethiopia this was 50%, and in Yemen 82% of men and 43% of women
admitted they currently used khat.
3.5
There are no reports of khat use in the UK outside of the
communities that traditionally use khat.
4. Import, export, distribution and use of khat in the UK
4.1
Approximately 6 tons of khat arrives in the UK per week, mostly by
air from Kenya. The bulk of this is in transit for supply to the
United States of America. The UK is a base for khat distribution to
many countries, including the US, where the plant is illegal.
4.2
There is an efficient distribution network to the khat using
communities across the UK. Most users buy khat at the mafresh,
a meeting place where khat is bought and chewed. Mafreshi proprietors often sell soft drinks and cigarettes alongside khat.
The trade in khat is a legitimate business and is quite distinct
from the trade in illegal drugs.
4.3 Mafreshi are subject to health and safety requirements as they
are public places where a product is sold and consumed, however many
are unknown to the local authorities. They are of varying standards
of cleanliness and safety. Alternatively khat is bought at local
shops, in markets or via ‘mobile traders’ (people selling khat from
the back of a car or van on the street).
4.4 Men
are more likely to use at the mafresh and women are more
likely to use at home, often alone. There is under-reporting of
women’s use of khat probably as a result of the extra stigma they
face.
4.5 Khat
is used in bundles of approximately 250g of fresh stems and leaves;
each bundle costs £3-5 (approximately £15/kg). In the United States
of America, where khat is illegal, the street price is approximately
$400/kg.
4.6 Most
people who use khat, chew it once or twice a week. The average
chewing session lasts 6 hours and usually 1 or 2 bundles of khat are
consumed. A significant minority chew daily and use greater amounts
per day. 5.
The pharmacology of khat
5.1
Cathinone and cathine are alkaloid stimulants present in khat and
are responsible for its subjective effects. Chewing is an efficient
way of extracting these chemicals from the plant matter. Khat
degrades with time so it must be consumed within 36 hours of
harvesting.
5.2
Effects from chewing khat can be felt within 30minutes, but maximal
plasma concentrations occur after about 2 hours. The time taken for
the drugs to be eliminated from the blood is approximately 8-20
hours for cathinone and 25 hours for cathine. 5.3
There is evidence that khat, like other drugs of misuse, can cause
the release of the neurochemical dopamine in the brain. Dopamine is
thought to be responsible for the re-enforcing properties of drugs
of abuse. Khat may also act on central serotonergic and peripheral
adrenergic neurotransmitter systems.
6.
Risks to physical health
6.1
There is evidence that chewing khat is a risk factor for the
development of oral cancers. In pre-clinical and clinical studies,
chewing khat leads to macroscopic and microscopic pre-cancerous
changes in the buccal mucosa.
6.2 Khat
has significant sympathomimetic properties. Chewing khat leads to an
increase in blood pressure and may precipitate myocardial
infarction. It is difficult to tease out the specific risk factor of
khat for heart disease as most users also smoke tobacco during a
khat session. 6.3
There is some evidence that khat affects the reproductive health of
both sexes. In women it may be associated with delivery of low birth
weight babies (as with smoking cigarettes), although the evidence
for this is not strong. Cathine is excreted in breast milk although
the impact of this is unknown.
6.4 In
men there is some evidence that using khat is associated with lower
sperm motility and sperm count. Some studies report an increase in
libido when using khat and others have found decreased libido with
chronic use of khat. 6.5
Residual pesticide, dimethoate, has been found on khat leaves
produced in Yemen. There is no published data on khat produced in
other countries. Chronic dimethoate poisoning can lead to weakness,
fatigue, slurred speech and lack of co-ordination.
6.6 Khat
administered chronically to animals causes an increase in liver
transaminases and signs of chronic hepatic inflammation. There are
no studies investigating the effects of khat on the hepatic system
in humans.
7. Risk of addiction and to psychiatric health
7.1
There is evidence that khat may cause the release of dopamine in the
brain. Release of this neurotransmitter is thought to be important
in the development of dependency on drugs of abuse.
7.2
Dependency on a drug is defined as a syndrome of symptoms related to
the desire to use a drug, the control over drug use, tolerance of
drug effects, withdrawal symptoms, harms from drug use and neglect
of other activities of life. 7.3
There is evidence that some individuals use khat in a dependent way.
However, for the majority of users this does not appear to be the
case. Animals can be made dependent on khat and they will
self-administer the drug in a dependent way.
7.4
There are case reports of people developing psychosis after use of
khat. Unfortunately, as yet, there are few controlled studies
investigating the possibility of a causal link between khat use and
psychosis. Evidence points to social stress such as the effects of
war on the Somali population mixed with misuse of khat can increase
the likelihood of the development of psychotic symptoms.
7.5 As
yet there is insufficient evidence to make a definitive statement
about the risks of developing psychosis after using khat. However,
in countries where khat use is widespread there is no corresponding
elevation in prevalence of psychotic disorders. This suggests that
khat is not a causal factor for the development of psychosis.
7.6 In
common with other stimulants, users of khat often report feeling low
in mood after a khat using session. However, there is no evidence
that khat use is a risk factor for developing depression.
8.
Risk to society
8.1 The
partners of khat users often complain that their partners’ khat use
is responsible for lack of input into family life, for family
arguments, and leads to excessive expenditure of the family budget.
It is cited as a reason for family breakdown by spouses, and there
is a fear that men using excessively (as heads of the family unit)
lead to isolation for their spouses and children. It is impossible
to say if khat use is the cause of or the scapegoat for family
disharmony.
8.2 Khat
users appear to have very low levels of other drug or alcohol use.
There is no evidence that khat use is a gateway to the use of other
stimulant drugs, although there is however, high associated tobacco
use. 8.3 Khat
does not lead to acquisitive crime in the way that is evident with
crack or heroin use. This may be due to its low cost and its lower
re-enforcing properties.
8.4
There is evidence that administering khat to rats causes an increase
in aggressive behaviour. There is only anecdotal evidence of the
same response in humans. 8.5
There are several case reports of individuals using khat and
driving. Khat is likely to reduce attention span whilst driving,
however co-ordination appears to be minimally affected.
8.6 The
khat industry is a legitimate business. There is no indication of
organised criminals or terrorists being involved in the UK trade,
perhaps because of its legality. However, since the USA made khat
illegal there is some evidence of organised criminals becoming
involved in its shipment to the USA.
9.
Discussion
9.1 Existing
evidence suggests that khat use is widespread in the UK among immigrant
communities from the Horn of Africa and the Arabian Peninsula. There is
no evidence of its use by the wider community.
9.2 Khat is
a much less potent stimulant than other commonly used drugs such as
amphetamine or cocaine. However some individuals use it in a dependent
manner. 9.3 Khat use
is a risk factor for oral cancers and possibly for myocardial
infarction. Residual pesticides on the leaves of khat represent a health
risk.
9.4 There is
some evidence of an association with chronic khat use and development of
psychological symptoms. However, as yet there is
no proven causal association.
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