Download Chapter 3.Litho

Part 3:
The health
and social
consequences
of drug abuse
Contents
INTRODUCTION
The principal characteristics of the drugs covered
by this report are their potential for altering mood
and behaviour and for creating dependence. Although many of them have considerable therapeutic value, they are also widely misused, thereby
creating a series of adverse consequences for
society. The aim of this chapter is to examine the
different kinds of drug which are abused and to
consider their impact on the individual and the
community.*
Nerve cells in the brain communicate with each
other by means of naturally produced chemicals
known as neurotransmitters. A cell releases a neurotransmitter into the space between nerve endings
known as the synapse; the molecules are then
picked up by receptor proteins on the surface of the
second cell. In the normal course of its activities the
brain releases and absorbs neurotransmitters such
as dopamine, norepinephrine and serotonin. Many
drugs, including those with addictive potential,
work by imitating or releasing these neurotransmitters or by blocking their actions. Blocking drugs,
which occupy drug receptor sites in the brain and
bind to them, are known as antagonists, while imitating drugs are known as agonists. The existence
of different pathways in the brain means there are
many different types of neurotransmitter and many
different kinds of receptor, and the type of effect a
drug produces depends on the type of neurotransmitter it reacts with. Cocaine, for example, blocks
the brain’s ability to reabsorb dopamine, with the
result that the neurotransmitters remain trapped in
the synapse, stimulating the receptors over and
over again. Prolonged stimulation causes the
reward, or pleasure associated with the drug. The
greater the reward, the greater is the inclination to
repeat the experience.
In laboratory studies the dependence potential of a
drug can be measured by how long and hard an
animal will work to maintain supplies. In human
beings, physical dependence is characterized by
drug-specific withdrawal symptoms and ‘craving’ –
a slavish urge to find and consume more of the
drug. This condition is both psychological and
physiological, but has a biochemical explanation:
the body’s ability to reproduce chemicals naturally
becomes depleted by artificial chemical stimulation, causing a deficiency when the drug is no
longer available.
Tolerance occurs when repeated use of a drug
requires the consumer to increase dosage in order
to experience the same “high”. Cross tolerance
exists within a specific drug type, for example the
synthetic opiate methadone shows cross tolerance
with morphine, while reverse tolerance implies an
increased responsiveness as a result of past consumption. The shortest time that must elapse
before repetition of the dose has a similar effect to
the one before is called the critical interval.
Cocaine is chemically processed or metabolized
much faster than heroin and therefore has a much
shorter critical interval.
The health consequences of psychoactive drug use
depend on the interaction of two sets of variables,
namely the characteristics of the drug and those of
the consumer.
The former include
• pharmacological properties;
• route of administration, i.e. oral ingestion, snorting, inhalation, injection (subcutaneous, intravenous or intramuscular);
• whether it is taken alone or together with other
drugs or alcohol;
• level of purity and presence of adulterants;
• dosage level.
The latter include
• personality of the user;
• intensity or frequency of previous use;
• user’s pre-existing state of health;
• social and economic circumstances of the user;
• the user’s expectations of the drug’s effects
(see Part 2).
The existence of so many variables means that
the effects of drugs can differ widely from one
* The authors acknowledge a debt throughout this chapter to UNDCP, The Social Impact of Drug Abuse, a Position Paper for the World Summit for Social
Development (UNDCP/TS.2, Vienna, 1996).
Contents
71
individual to another. Some people may suffer no
serious side effects from a single experiment with
drugs while for others it may be the beginning of a
illicit drug use is that the consumer – the last buyer
in what may be a long chain of distribution – is
rarely able to verify the dosage or the purity of the
purchase. The absence of quality control and
the furtive conditions in which drugs are
Drugs can alter mood and behaviour
dealt and consumed may result in acute
poisoning – heroin may be diluted with
and create dependence. Consequences
strychnine or supplied in an excessively pure
of their use depend on characteristics
dose leading to death; gullible youngsters
buying drugs at a ‘rave’ party can have no
of both drug and consumer.
idea of what chemical cocktail is about to
bombard their brains.
lifetime addiction. Even a single experience can
provoke an acute toxic reaction, while chronic
Drug types are described in various ways, dependeffects come from the body’s response to regular,
ing on origin and effect. They can either be
long-term abuse. Either pattern of use can lead to
naturally occurring, semi-synthetic (chemical
dependence and to an impairment of the body’s
manipulations of substances extracted from natural
organs or its functions, or both. Unsupervised drug
materials) or synthetic (created entirely by laboruse may also have secondary effects in that it may
atory manipulation). The principal categories are as
conceal or delay recognition of genuine illnesses
follows:
requiring treatment.
1. Opiates: the generic name given to a group
Estimates of morbidity and mortality are used to
which includes naturally occurring drugs derived
gauge the consequences of acute and chronic drug
from the opium poppy (Papaver somniferum) such
abuse. Morbidity indicators help us to underas opium, morphine and codeine, semi-synthetic
stand the association of drugs with illness and
substances such as heroin (the foregoing are opidisease by providing information on the numbers
ates in the strictly correct definition); and opioids
and frequency of treatment requests, drug-related
– ‘opiate-like’, wholly synthetic products such as
emergency room incidents at public hospitals, hosmethadone, pethidine and fentanyl. Opiates
pitalizations and prevalence of communicable
depress the central nervous system and are used
diseases relating to drug use. Mortality data tell us
therapeutically as analgesics (painkillers), as cough
how many deaths are directly linked to the use of
suppressants and against diarrhoea; in non-medical
psychoactive drugs. Together these give us an estusage as euphoriants and as a means of reducing
imate of harmfulness.
anxiety, boredom, physical or emotional pain.
Heroin is often the opiate preferred by consumers
The term overdose is often applied in the case of
because it is relatively potent, easily dissolved in
drug-related mortality but in many cases death (or
water for injecting and penetrates the blood-brain
barrier more quickly than morphine. Effects
may last from 4 – 6 hours. Heroin can also
A single experience can provoke an acute
be snorted, smoked or inhaled by the
method known as ‘chasing the dragon’
toxic reaction, chronic effects come from
whereby it is heated on foil and the fumes
long-term abuse.
inhaled. The effects of methadone, which is
usually taken orally, may last up to 24 hours.
acute illness) may not be due to an excessive quantity of the drug but to an interaction with other
It can happen that opiate dependence brings few
psychoactive substances or with adulterants used
physical complications other than constipation, but
by retailers to bulk out the dosage units. These
such cases are rare; studies of British heroin addicts
impurities may do as much, if not more, harm than
in the 1960s showed that even when maintained
the drug itself. An important factor underlying all
on medically prescribed ‘clean’ heroin and supplied
72
Contents