Facts on File Encyclopedia of Health and Medicine

presence in the body. Because the body develops
TOLERANCEto many drugs taken on a long-term
basis (requiring a higher DOSEto achieve the same
effect), the longer the person uses the substance
the more likely he or she may experience some
physiologic and psychologic symptoms when stop-
ping the substance, representing the body’s adap-
tation to the drug’s absence. The nature of such
symptoms depends on the drug. Drugs often sub-
ject to abuse that cause psychologic dependence
include COCAINE, AMPHETAMINES, BENZODIAZEPINE
drugs, and HALLUCINOGENS.
Though drug dependence is often a key factor
in substance abuse and ADDICTION, it is not synony-
mous with either. Substance abuse and addiction
encompass the ways in which people use the
drugs and the behaviors in which they engage to
obtain the drugs. Physiologic dependence occurs
in numerous therapeutic applications—for exam-
ple, with therapies involving systemic CORTICO-
STEROID MEDICATIONS, ANTIDEPRESSANT MEDICATIONS,
and antihypertensive medications. As well, a per-
son may develop dependence on a substance com-
monly abused (such as a narcotic PAINreliever or
antianxiety medication) when taking it to legiti-
mately treat a health condition and yet not abuse
or have an addiction to that substance.

Symptoms and Diagnostic Path
Indications of drug dependence vary according to
the drug. In a therapeutic context such symptoms
reflect achievement of the desired effect of the
drug—for example, suppression of the IMMUNE
RESPONSEwith corticosteroid medications or relief
of symptoms with antidepressant medications or
pain relief medications. In the context of sub-
stance abuse or addiction, indications of drug
dependence may include attempts to obtain
increasing quantities of the drug, taking the drug
inappropriately, and obvious differences in behav-
ior between when taking the drug and when not
taking the drug.

Treatment Options and Outlook

Treatment for undesired or unintentional drug
dependence, such as with corticosteroid or antide-
pressant medications, consists of controlled wean-
ing from the drug, a process that may take several
weeks to complete. In circumstances in which

there is also substance abuse or addiction, exten-

sive support and treatment such as PSYCHOTHERAPY

are also essential. Though physiologic dependence

ends when the drug is no longer present in the

body, psychologic dependence can persist for

weeks, months, or even years after stopping the

drug.

Risk Factors and Preventive Measures

The primary risk factor for drug dependence is

taking repeated doses of the drug. When doing so

is to achieve therapeutic outcomes, drug depen-

dence is desired and appropriate. When the pur-

pose of taking a drug is other than therapeutic,

not only is dependence possible but there is a high

likelihood for substance abuse or addiction. As

such use is detrimental to health, prevention

efforts include restricting access to the drug along

with education and therapy, if appropriate, to

understand the health consequences of continued

dependence and behavioral approaches to avoid

use of the drug.

See also ANALGESIC MEDICATIONS; ILLICIT DRUG USE;

PRESCRIPTION DRUG ABUSE; SCHEDULED DRUGS; SUB-

STANCE ABUSE PREVENTION; SUBSTANCE ABUSE TREAT-

MENT.

depressants Chemicals that slow the activity of

the CENTRAL NERVOUS SYSTEM. The primary thera-

peutic purpose of depressants is to cause sedation

or sleep. Most work through actions that directly

affect the function of BRAINneurons, neurotrans-

mitters, and neuroreceptors. Many do so by

increasing the activity of gamma aminobutyric

acid (GABA), a NEUROTRANSMITTERthat slows brain

function. Depressants have high potential for

DEPENDENCEand ADDICTION. Abruptly ending their

use may cause WITHDRAWAL SYNDROMEthat, with

certain drugs, has the potential to be life threaten-

ing when symptoms are serious and untreated.

Types of prescription drugs that are depressants

include ANTIANXIETY MEDICATIONS, HYPNOTICS, BARBI-

TURATES, and BENZODIAZEPINES. Drugs in these classi-

fications are SCHEDULED DRUGSin the United States,

which require a physician’s prescription for legal

possession and use. Doctors may prescribe them to

treat GENERALIZED ANXIETY DISORDER (GAD), panic

attacks and PANIC DISORDER, SLEEP DISORDERS, and

POST-TRAUMATIC STRESS DISORDER(PTSD).

depressants 331