Subject(s): CANNABIS -- Europe; DRUGS -- Europe
As we reach into at least the third decade of prevalent cannabis use
of the modern era, is it just possible that we are beginning to
observe the maturation of discussion on some cannabis-related issues?
Cannabis remains a hot policy topic with strong degrees of
polarization of views on the risks and benefits of cannabis. Cannabis
is now by far the most commonly consumed illicit drug, with 10-30% of
the population in Europe reporting ever use and significant reports of
chronic usage in some countries.
This scale of usage and the gradual normalization of consumption in
some populations allows for greater possibilities for more accurate
epidemiological studies based partially on a readiness to self-report
honestly on cannabis use and also because the greater prevalence of
use allows for easier access to populations to study.
The growth in the size of the using population and in particular the
availability of populations of chronic heavy users now opens thedoors
for more precise studies of the long-term impact of heavy usage. There
are now some studies of the characteristics of long-term users (Swift
et al., 1998) and there appears to be a growing number of studies of
strategies for assisting in the cessation of cannabis use.
Inability to cut down or stop cannabis use is a real phenomenon which
has received surprisingly limited attention until recently. This is
presumably linked to the debate on whether or not cannabis is
addictive. This is a somewhat curious debate, given the animal
literature on the subject. Tolerance to cannabis, withdrawal from
cannabis and dependence on cannabis is demonstrated clearly in animals
(Pertwe, 1991). Recent antagonist studies further confirm these
withdrawal phenomena (Aceto et al., 1996). Withdrawal phenomena in
humans have also been reported with much of the work being done in the
1970s. Jones (1983) has reviewed this topic comprehensively and
reports that the signs of cannabis withdrawal have been relatively
mild and are comparable to the symptoms of withdrawal from short,
low-dose treatment with opioids or ethanol. These symptoms may be
dose-related. Irritability and increased aggression may be associated
with withdrawal in chronic cannabis users. Budney et al., in this
issue, report on a small sample of treatment seekers who were
experiencing withdrawal symptoms. However, there are always problems
differentiating withdrawal symptoms from other mood and anxiety
symptoms in a population presenting to a treatment service. Swift et
al. (1998) have reported on dependence in cohorts of long-term
cannabis users. They reported limited withdrawal phenomena but argued
that this may be related to the sample's ready access to cannabis on a
continuous basis. Large-scale population studies report significant
rates of cannabis dependence (Kessler et al., 1994; Farrell et al.,
1998), particularly in prison and homeless populations.
Does this now mean that there is no controversy around the dependence
liability of cannabis? Well, not exactly. We can now agree that many
people meet internationally agreed criteria for dependence but we are
still not sure what it means and what significance it has for the
individual, for the clinician or on a public health level.
Dependence and the nature of dependence as described originally was a
dimensional description of a provisional nature (Edwards & Gross,
1976). Overall there is a need for careful exploration of the meaning
and nature of cannabis dependence and its overall clinical utility and
public health significance. Such work is likely to be richly
productive in an era with a growing population of heavy cannabis
users, some of whom seek help to stop their smoking habit. Cannabis as
a habit is here to stay.
References
BUDNEY, A., Novy, P. & HUGHES, J. (1999) Marijuana withdrawal among
adults seeking treatment for marijuana dependence, Addiction, 94,
1311-1321.
EDWARDS, G. & GROSS, M. M. (1976) Alcohol dependence: provisional
description of a clinical syndrome, British Medical Journal, 1,
1058-1061.
FARRELL, M., HOWLS, S., TAYLOR, C. et al. (1998) Substance misuse and
psychiatric comorbidity: an overview of the OPCS national psychiatric
morbidity survey, Addictive Behaviour, 23, 909-918.
JONES, g. T. (1983) Cannabis withdrawal, in: FEHR, K. & KALANT, H.
(Eds) Cannabis and Health Hazards, pp. 617-689 (Toronto, Addiction
Research Foundation).
KESSLER, R., MCGONAGLE, K., ZHAO, S. et al. (1994) Lifetime and 12
month prevalence of DSM-III-R psychiatric disorders in the United
States: results from the National Comorbidity Survey, Archives of
General Psychiatry, 51, 8-19.
PERTWEE, R. (1991) Tolerance and dependence on psychotropic
cannabinoids, in: PRATT, J. A. (Ed.) The Biological Basis of Drug
Tolerance and Dependence, pp. 232-263 (San Diego, CA, Academic Press).
SWIFT, W., HALL, W., DIDCOTT, P. & REILLY, D. (1998) Patterns and
correlates of cannabis dependence among long term users in an
Australian rural area, Addiction, 93, 1149-1160.
~~~~~~~~
By S-Michael Farrell, Senior Lecturer and Consultant Psychiatrist,
National Addiction Centre, 4 Windsor Walk, London SE5 8AF, UK
Cannabis dependence and withdrawal.
Source: Addiction, Sep99, Vol. 94 Issue 9, p1277, 1p
Author(s): Farrell, Michael
Abstract: Editorial. Focuses on the drug, cannabis. Scale usage and
normalization of consumption at some populations in Europe; Growth in
the size of the using population; Inability to cut down or stop
cannabis use; Nature of dependence.
AN: 2301745
ISSN: 0965-2140
Database: Academic Search Elite
Section: EDITORIAL
CANNABIS DEPENDENCE AND WITHDRAWAL