develops most frequently with drugs
that alter mood or behaviour.
Drug dependence may cause physical
problems, such as lung and heart dis-
ease from smoking and liver disease
from excessive alcohol consumption.
Mental problems, such as anxiety and
depression, are common during with-
drawal. Dependence may also be linked
with drug tolerance, in which increas-
ingly higher doses of the substance is
needed to produce the desired effect.
Complications, such as hepatitisor
AIDS, contracted as a result of intro-
ducing infection into the bloodstream
via a dirty needle, may occur. Abusers
may suffer from an overdose because of
confusion about the dosage or because
they take a purer, more potent prepara-
tion than they are used to.
drug interaction The effect of a drug
when it is taken in combination with other
drugs or with substances such as alcohol.
drug overdoseThe taking of an exces-
sive amount of a drug, which may cause
toxic effects (see drug poisoning).
drug poisoningThe harmful effects on
the body as a result of an excessive dose
of a drug. Accidental poisoning is most
common in young children. In adults, it
usually occurs in elderly or confused peo-
ple who are unsure about their treatment
and dosage requirements. Accidental
poisoning may also occur during drug
abuse. Deliberate self-poisoning is usu-
ally a cry for help (see suicide; suicide,
attempted). The drugs that are most
commonly taken in overdose include
benzodiazepine drugs and antidepressant
drugs. Anyone who has taken a drug
overdose and any child who has swal-
lowed tablets that belong to someone
else should seek immediate medical
advice. It is important to identify the
drugs that have been taken. Treatment
in hospital may involve washing out the
stomach (see lavage, gastric). Charcoal
may be given by mouth to reduce the ab-
sorption of the drug from the intestine
into the bloodstream. To eliminate the
drug, urine production may be increased
by an intravenous infusion. Antidotes are
available only for specific drugs. Such
antidotes include naloxone(for mor-
phine) and methionine (for paracetamol).Drug poisoning may cause drowsiness
and breathing difficulty, irregular heart-
beat, and, rarely, cardiac arrest, fits, and
kidney and liver damage. Antiarrhyth-
mic drugsare given to treat heartbeat
irregularity. Fits are treated with anti-
convulsants. Blood tests to monitor liver
function and careful monitoring of urine
output are carried out if the drug is
known to damage the liver or kidneys.
dry eyeSee keratoconjunctivitis sicca.
dry iceFrozen carbon dioxide. Carbon
dioxide changes from a gas to a solid
when cooled, without passing through a
liquid phase. Dry ice is sometimes
applied to the skin in cryosurgery, a tech-
nique used, for example, to treat warts.
dry socketInfection at the site of a
recent tooth extraction, causing pain, bad
breath, and an unpleasant taste. Dry
socket occurs when a blood clot fails to
form in the tooth socket after a difficult
extraction, such as removal of a wisdom
tooth (see impaction, dental). Sometimes,
the clot itself becomes infected, or infec-
tion may already have been present before
extraction. The inflamed socket appears
dry, and exposed bone is often visible.
The socket is irrigated to removedebris
and may then be coated with an anti-
inflammatory paste. The infection usually
begins to clear up within a few days.
DSM IVThe 4th edition of the “Diag-
nostic and Statistical Manual of Mental
Disorders”, published by the American
Psychiatric Association in 1994. It clas-
sifies psychiatric illnesses and is widely
accepted in other countries.
dual personalitySee multiple person-
ality.
ductA tube or a tube-like passage lead-
ing from a gland to allow the flow of
fluids, for example, the tear ducts.
dumbnessSee mutism.
dumping syndromeSymptoms that
include sweating, fainting, and palpita-
tions due to the rapid passage of food
from the stomach into the intestine. It is
uncommon but mainly affects people
who have had a gastrectomy. Symptoms
may occur within about 30 minutes of
eating (early dumping) or after 90–120
minutes (late dumping). Some tense
people may have symptoms although
their stomach is intact.DRUG INTERACTION DUMPING SYNDROMED