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Depressants
Historically, people
of almost every culture have used chemical agents to induce sleep, relieve
stress, and allay anxiety. While alcohol is one of the oldest and most
universal agents used for these purposes, hundreds of substances have
been developed that produce central nervous system depression. These drugs
have been referred to as downers, sedatives, hypnotics, minor tranquilizers,
anxiolytics, and anti-anxiety medications. Unlike most other classes of
drugs of abuse, depressants are rarely produced in clandestine laboratories.
Generally, legitimate pharmaceutical products are diverted to the illicit
market. A notable exception to this is a relatively recent drug of abuse,
gamma hydroxybutyric acid (GHB).
Choral hydrate and
paraldehyde are two of the oldest pharmaceutical depressants still in
use today. Other depressants, including gluthethimide, methaqualone, and
meprobamate have been important players in the milieu of depressant use
and abuse. However, two major groups of depressants have dominated the
licit and illicit market for nearly a century, first barbiturates and
now benzodiazepines.
Barbiturates were
very popular in the first half of the 20th century. In moderate amounts,
these drugs produce a state of intoxication that is remarkably similar
to alcohol intoxication. Symptoms include slurred speech, loss of motor
coordination, and impaired judgment. Depending on the dose, frequency,
and duration of use, one can rapidly develop tolerance, physical dependence,
and psychological dependence to barbiturates. With the development of
tolerance, the margin of safety between the effective dose and the lethal
dose becomes very narrow. That is, in order to obtain the same level of
intoxication, the tolerant abuser may raise his or her dose to a level
that may result in coma or death. Although many individuals have taken
barbiturates therapeutically without harm, concern about the addiction
potential of barbiturates and the ever-increasing number of fatalities
associated with them led to the development of alternative medications.
Today, less than 10 percent of all depressant prescriptions in the United
States are for barbiturates.
Benzodiazepines were
first marketed in the 1960s. Touted as much safer depressants with far
less addiction potential than barbiturates, today these drugs account
for about one out of every five prescriptions for controlled substances.
Although benzodiazepines produce significantly less respiratory depression
than barbiturates, it is now recognized that benzodiazepines share many
of the undesirable side effects of the barbiturates. A number of toxic
central nervous system effects are seen with chronic high-dose benzodiazepine
therapy, including headaches, irritability, confusion, memory impairment
and depression. The risk of developing over-sedation, dizziness, and confusion
increases substantially with higher doses of benzodiazepines. Prolonged
use can lead to physical dependence even at doses recommended for medical
treatment. Unlike barbiturates, large doses of benzodiazepines are rarely
fatal unless combined with other drugs or alcohol. Although primary abuse
of benzodiazepines is well documented, abuse of these drugs usually occurs
as part of a pattern of multiple drug abuse. For example, heroin or cocaine
abusers will use benzodiazepines and other depressants to augment their
"high" or alter the side effects associated with over-stimulation
or narcotic withdrawal.
In recent years,
GHB has emerged as a significant drug of abuse throughout the United States.
Abusers of this drug fall into three major groups: (1) users who take
GHB for its MDMA-like hallucinogenic effects or as an intoxicant or euphoriant;
(2) bodybuilders who abuse GHB for its alleged utility as an anabolic
agent or as a sleep aid; and (3) individuals who use GHB as a weapon for
sexual assault. These categories are not mutually exclusive and an abuser
may use the drug illicitly to produce several effects. GHB is frequently
taken with alcohol or other drugs that heightens its effects and is often
found at bars, nightclubs, rave parties, and gyms. Teenagers and young
adults who frequent these establishments are the primary users. Like flunitrazepam,
benzodiazepine is often referred to as a "date-rape" drug, and
GHB involvement in rape cases is likely to be unreported or unsubstantiated.
GHB is quickly eliminated from the body making detection in body fluids
unlikely; and its fast onset of depressant effects may render the victim
with little memory of the details of the attack.
There are marked
similarities among the withdrawal symptoms seen with most drugs classified
as depressants. In the mildest form, the withdrawal syndrome may produce
insomnia and anxiety, usually the same symptoms that initiated the drug
use. With a greater level of dependence, tremors and weakness are also
present, and in its most severe form, the withdrawal syndrome can cause
seizures and delirium. Unlike the withdrawal syndrome seen with most other
drugs of abuse, withdrawal from depressants can be life threatening.
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