- Involves approximately
5.5 million people in the United States addicted to illegal
drugs; at least 20 million more abuse prescription medications.
- Costs the United
States government on drug law enforcement and criminal justice
an estimated $6.5 billion annually.
- Costs employers
an estimated $33 billion annually.
PROGRESS
IN MEDICAL RESEARCH
One of modern
society's major problems is that of drug abuse. It takes an
immeasurable toll each year in terms of lives, health cost,
crime, and productivity. Abuse is generally defined as "the
non-medical use of a drug that results in adverse consequences".
The major drugs of abuse can be grouped into nine broad categories:
- Narcotic Analgesics
(e.g., Morphine, Heroin)
- Depressants
(e.g., Barbiturates, Alcohol)
- Stimulants
(Amphetamines, Cocaine)
- Hallucinogens
(LSD, Mescaline)
- Marijuana
- Phencyclidine
(PCP)
- Nicotine
- Caffeine
- Inhalants (e.g.,
Nitrous Oxide)
Abuse of these
drugs can lead to the development of dependence upon them,
which can be either physical or psychological in nature. Physical
dependence is characterized by a well-defined withdrawal syndrome
following cessation of chronic drug use. This type of dependence
is most marked with narcotics and depressants and can be life-threatening
with the latter. Psychological dependence refers to chronic
drug-taking and is characterized by behavioral disruption
(i.e., drug-craving, drug-seeking behavior) following termination
of use. It appears to occur in varying degrees with all of
the above drug groups.
What
has animal research shown about drug abuse?
The reinforcing,
or rewarding properties of a drug can be determined by testing
whether or not an animal will self-administer the compound.
To date, it has been found that all addicting drugs used by
humans have similar effects on non-human primates, except
for marijuana and hallucinogens. This type of research yields
valuable information about the potential abuse of newly developed
drugs by comparing the effects with those of drugs that are
known to be addicting. Animal research has also shown how
important learning factors are in the maintenance and relapse
of drug-seeking behavior.
Is
animal research on drug abuse still needed?
With the constant
development of new drugs it is important to be able to evaluate
the potential for dependence in animals before being marketed
for human use. Animal research can also provide insights into
the multiple factors responsible for drug abuse. For instance,
identifying the exact neural systems involved in producing
the reinforcing effects of drugs may stimulate the development
of drugs which selectively block these effects as a treatment
for drug abuse. Similarly, animal research will help in understanding
how to treat psychological depend-ence by allowing us to study
the behavioral and environmental factors involved in drug
abuse.
What's
ahead for research on drug abuse?
Future research
is aimed at developing specific pharmacologic treatments to
prevent or attenuate drug abuse. Currently this approach is
aiding heroin abusers (methadone maintenance); alcoholism
(disulfiram, naltrexone); and tobacco dependence (nicotine
patches and gum). Further research may lead to the development
of treatments for other abused drugs such as cocaine. A complementary
approach to pharmacologic therapy is behavioral therapy which
may reduce drug-seeking behavior and craving. Animal research
will continue to play an important role in the direction of
future research.when a cure for diabetes is found.
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