- Afflicts at
least 20 million Americans.
- Is associated
with as many as 70% of suicides in the U.S.
- Annually accounts
for approximately 10% ($33 billion) of all direct health
care costs.
PROGRESS
IN MEDICAL RESEARCH
Mental illness
is a major public health problem in the United States. Several
categories of mental illness are currently recognized:
Major Affective
(Mood) Disorders, which involve sustained change in emotional
states. Major depression, for example, may cause suicidal
thoughts and feelings of worthlessness.
Schizophrenic
Disorders, causing symptoms including delusions, hallucinations,
as well as impaired body movements and speech.
Anxiety Disorders,
which may have an incapacitating and pervasive influence on
patients' lives. Panic disorder, for example, results in unpredictable
episodes during which sufferers experience an overwhelming
sense of terror.
What
has animal research shown about mental illness?
Our knowledge
of normal brain function and development has been a product
of animal research, from pioneering studies on how brain cells
transmit, to the most recent findings detailing how drugs
act on the brain. These studies have given researchers insight
into the effects of drugs used for the treatment of mental
illness and into the nature of the illness itself. They have
also led to a better understanding of the relationship between
brain function and behavior. Much of our current understanding
of schizophrenia, for example, has its roots in investigations
on the effects of early antischizophrenic drugs on animal
behavior and brain tissues. These studies have resulted in
the discovery of safer and more effective drugs, leading to
drastic reductions of the inpatient population of psychiatric
hospitals in the last three decades. Animal research also
can be used to predict the treatment potential of novel compounds;
for example, safer drugs for the treatment of anxiety and
depression have been developed based on crucial information
about their behavioral effects in animals.
Is
animal research on mental illness still needed?
More extensive
knowledge on the mechanisms that are affected in mental illness
could lead to the development of better drugs for its treatment.
This knowledge can most efficiently be obtained through research
centering on animal behavior and the brain. The development
of more specific animal research methods predicting the effectiveness
of new treatments for several disorders is another objective
to be pursued.
What
lies ahead?
Since the introduction
of neuro-leptics (tranquilizers that have therapeutic effects)
for the treatment of Schizophrenic Disorders (which affect
approximately one percent of the U.S. population at least
once in their lives), many patients have been relieved from
threatening hallucinations and ideas. But although neuroleptics
have been proven to be very effective, the currently available
drugs may cause disturbances in the coordination of movement,
dysphoria (depression, restlessness), or bone marrow depression.
In the treatment of Mood Disorders, especially depression
(which approximately five percent of people suffer from at
least once in their lives), only one-third of patients respond
satisfactorily and consistently to drug treatment and supporting
psychotherapy. Animal research has already played an important
role in developing treatments for mental illness. Future research
may lead to the development and use of drugs that improve
and efficiently stabilize these disorders while showing fewer
side effects.millions.
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