- Drug availability and economic factors: Rates of dependence
are increased if a drug is easily available. This may
explain why dependence on nicotineandalcoholis a
much greater public health problem than dependence on
illegal drugs, because of their greater availability. Drug
use is sensitive to price (e.g. rates of alcoholism are
reduced by increasing alcohol prices). - Biochemical reinforcement: Drugs of abuse and
dependence have a common biochemical pathway:
they all increase dopamine in the nucleus accumbens,
associated with mood elevation and euphoria.
Behaviourally, this is linked with reinforcement of drug-
taking. Dependence-potential of different drugs is related
to potency in releasing dopamine (cocaineis most potent).
The rate of dopamine release is also important, e.g.
smoked and intravenous drugs give a more rapid effect
than oral drugs.
GENERAL PRINCIPLES OF TREATING
ADDICTIONSBy the time an addict presents for assessment and treatment,
he or she is likely to have diverse and major problems. There
may be physical or mental illness, and emotional or attitu-
dinal problems, which may have contributed to the addiction
and/or resulted from it. Their financial and living circum-
stances may have been adversely affected by their drug habit
and they may have legal problems relating to drug possession,
intoxication (e.g. drink–driving offences), or criminal activ-
ities carried out to finance drug purchases. Attitudes to drug
use may be unrealistic (e.g. denial). The best chance of a suc-
cessful outcome requires that all of these factors are con-
sidered, and the use of a wide range of treatment options is
likely to be more successful than a narrow repertoire.
Treatment objectives vary depending on the drug.
Complete abstinence is emphasized for nicotine,alcoholor
cocaineaddiction, whereas for heroinaddiction many patients
benefit from methadonemaintenance. Other objectives are to
improve the health and social functioning of addicted patients.
Treatment success can only be determined over a long time,
based on reduction in drug use and improvements in health
and social functioning. A treatment programme should
include medical and psychiatric assessment and psychological
and social support. Addicts should be referred to specialist
services if these are available. Other services based in the vol-
untary sector (e.g. Alcoholics Anonymous) are also valuable
and complementary resources. Medical and psychiatric assess-
ment may need to be repeated once the patient is abstinent, as
it is often difficult to diagnose accurately certain disorders in
the presence of withdrawal symptoms (e.g. anxiety, depression
and hypertension are features of alcohol withdrawal, but are
also common in abstinent alcoholics).
The pharmacological treatment of addictions, which includes
treatment of intoxication, detoxification (removal of the drug
from the body, including management of withdrawal symp-
toms) and treatment to prevent relapse, is discussed below.
OPIOID/NARCOTIC ANALGESICS
Diamorphine (‘heroin’) is preferred by most opioid addicts.
It is often adulterated with other white powders, such as qui-
nine(which is bitter, like opiates), caffeine, lactose and even
chalks, starch and talc. Due to the variable purity, the dose
of black-market heroinis always uncertain. The drug is
taken intravenously, subcutaneously, orally or by inhalation of
smokedheroin. In addition to the illegal supply of heroinfrom
Afghanistan and elsewhere, opioids are obtained from phar-
macy thefts and the legal prescription of drugs for treatment of
the addiction. Some of the drugs used are listed in Table 53.1.
The pharmacological actions of opioids are described in
Chapter 25 and their effects on the central nervous system
(CNS) are summarized in Table 53.2.MEDICAL COMPLICATIONSMedical complications of opioid addiction are common and
some of them are listed in Table 53.3. The majority of these
relate to use of infected needles, the effects of contaminating
substances used to cut supplies or the life-style of opioid
addicts. These are the principal reasons for the development
of methadone clinics and needle-exchange programmes434 DRUGS AND ALCOHOL ABUSE
Table 53.1:Opioid drugs that are commonly abusedDrugs Comment
Diamorphinea Mainly obtained on the black market. It is of
variable purity and cut with quinine, talc,
lactose, etc. It is usually mixed with water,
heated until dissolved, and sometimes
strained through cotton. It may be used
intravenously (mainlining), subcutaneously
(skin popping) or inhaled (‘snorted’/
’chasing the dragon’, by heating up on foil
and inhaling the smoke) (t1/260–90 min)
Methadone This is the mainstay of drug addiction clinics,
and is usually given as an elixir (long t1/2
of 15–55 h). It is very difficult to use elixir
for injection
Dipipanone Previously much used by non-clinic doctors
( cyclizine treating addicts. It is easily crushed up and
Diconal®)a dissolved for intravenous use
Other opoids All opioids, including mixed
agonists/antagonists (e.g. buprenorphine)
have the potential to cause dependence
aDiamorphine, dipipanone and cocaine (not an opioid) can only be
prescribed to addicts for treatment of their addiction by doctors with a
special licence.