Provided by the National Institute of Mental Health
More than 19 million adult Americans ages 18 to
54 have anxiety disorders. The National Institute of Mental Health (NIMH)
supports research into the causes, diagnosis, prevention, and treatment of
anxiety disorders and other mental illnesses. This research is conducted both in
the Institute's intramural laboratories and in biomedical research institutions
across the country. Studies examine the genetic and environmental risks for
major anxiety disorders, their course, both alone and when they co-occur with
other illnesses such as heart disease or depression, and their treatment.
Scientists seek to discover the basis of anxiety disorders in the brain and
their effects on the functioning of the brain and other organs. The ultimate
goal is to be able to cure, and perhaps even to prevent, anxiety disorders.
Types of Anxiety Disorders
The term anxiety disorders encompasses several clinical conditions:
panic disorder, in which feelings of extreme fear and dread strike unexpectedly
and repeatedly for no apparent reason, accompanied by intense physical symptoms
obsessive-compulsive disorder (OCD), characterized by intrusive, unwanted,
repetitive thoughts and rituals performed out of a feeling of urgent need
post-traumatic stress disorder (PTSD), a reaction to a terrifying event that
keeps returning in the form of frightening, intrusive memories and brings on
hypervigilance and deadening of normal emotions
phobias, including specific phobia a fear of an object or situation and social
phobia a fear of extreme embarrassment
generalized anxiety disorder (GAD), exaggerated worry and tension over everyday
events and decisions
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About NIMH
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Research Progress
NIMH research has led to advances in understanding the causes of these disorders
and how to treat them. Today, the majority of people with panic disorder and OCD
improve significantly within weeks or months of getting proper treatment. The
same is true for people with phobias. And many people with PTSD and generalized
anxiety disorder also make substantial improvement with treatment.
As the search continues for better treatments, NIMH is harnessing the most
sophisticated scientific tools available to determine the causes of anxiety
disorders. Like heart disease and diabetes, these brain disorders are complex
and probably result from the interplay of genetic, behavioral, developmental,
and other factors. Scientists in a number of disciplines are trying to identify
risk factors that make certain people prone to these conditions.
Studies of the Brain and Anxiety Disorders
Studies in animals and humans have focused on pinpointing the specific brain
areas and circuits involved in anxiety and fear, which underlie anxiety
disorders. Fear, an emotion that evolved to deal with danger, causes an
automatic, rapid protective response that occurs without the need for conscious
thought. It has been found that the body's fear response is coordinated by a
small structure deep inside the brain, called the amygdala.
Neuroscientists have shown that when confronted with danger, the body's senses
launch two sets of signals to different parts of the brain. One set of signals,
which takes a more roundabout route, relays information to the cerebral cortex,
the cognitive part of the brain that explains in detail the threatening object
or situation such as a big black car heading for you as you cross the street.
The other set of signals shoots straight to the amygdala, which sets the fear
response in motion, readying the body for quick action before the cognitive part
of the brain comprehends just what is wrong. The heart starts to pound and
diverts blood from the digestive system to the muscles for quick action. Stress
hormones and glucose flood the blood stream to provide the energy to fight or
flee. The immune system and the pain response are suppressed to prevent swelling
and discomfort, which could interfere with a quick escape. And, as a preventive
measure for similar confrontations in the future, the learned fear response is
etched on the amygdala.
What Are the Treatments for Anxiety Disorders?
Treatments have been largely developed through research conducted by NIMH and
other research institutions. They are extremely effective and often combine
medication and specific types of psychotherapy.
More medications are available than ever before to effectively treat anxiety
disorders. These include antidepressants and benzodiazepines. If one medication
is not effective, others can be tried. New medications are currently being
tested or are under development to treat anxiety symptoms.
The two most effective forms of psychotherapy used to treat anxiety disorders
are behavioral therapy and cognitive-behavioral therapy. Behavioral therapy
tries to change actions through techniques such as diaphragmatic breathing or
through gradual exposure to what is frightening. In addition to these
techniques, cognitive-behavioral therapy teaches patients to understand their
thinking patterns so they can react differently to the situations that cause
them anxiety.
How Does this Learned Fear Response Turn into an Anxiety Disorder?
One or more fearful experiences can prime a person to respond excessively to
situations where most people would experience no fear—such as in the
supermarket—or only moderate nervousnesss—such as giving a speech. In anxiety
disorders, the deeply etched memory can result in hypervigilance, making it hard
to focus on other things, and leading to feelings of anxiety in many situations.
In people who have survived overwhelming trauma and developed PTSD, for example,
even mild reminders of the trauma may initiate the fear response. People with
specific or social phobia often completely avoid their feared situation. In
panic disorder the chronic worry about having another attack may lead to
stress-related conditions such as heart problems and irritable bowel syndrome.
In people with generalized anxiety disorder, the chronic anxiety may prevent
them from focusing on even the simplest tasks. The amygdala, although relatively
small, is a very complicated structure, and recent research with animals
suggests that different anxiety disorders may be associated with activation in
different parts of the amygdala.
Brain Findings Point the Way to New Approaches
The amygdala findings may have important implications for treating people who
suffer from anxiety disorders. If, as studies suggest, the memories stored in
the amygdala are relatively indelible, one aim of research is to develop
therapies for anxiety disorders that increase cognitive control over the
amygdala so that the "act now, think later" response can be interrupted.
Clinical Trials of New Treatments
Anxiety disorder treatment studies have been designed so that pharmacological
and cognitive or behavioral therapies can be tested head-to-head. In one
clinical trial, two separate centers are examining how well drug and behavioral
therapies work separately and together in the treatment of OCD. Data collected
from this study should help scientists determine if one of the treatments works
better than the other in decreasing obsessions and compulsions. In addition, the
direct comparison of the combined treatment with the medication will provide
much needed information on whether the high relapse rate associated with
stopping the drug can be reduced. The comparison should also help determine if
the medication can enhance compliance with the behavioral treatment.
Many of the current medications for anxiety disorders affect the
neurotransmitter serotonin. New treatment approaches are examining drugs that
affect other neurotransmitters and brain chemicals such as GABA, gamma-aminobutyric
acid, and Substance P. A new research tool, magnetic resonance spectroscopy will
help scientists measure brain levels of GABA and other substances.
Researchers are also looking at combinations of medications that may have a
synergistic effect—in panic disorder, for example, studies are underway to
determine if an antidepressant medication that affects serotonin works better
when used with the new antianxiety drug buspirone.
The Role of Cognitive Factors
Cognitive factors play a significant role in the onset of anxiety disorders.
People at risk for these disorders tend to be overly responsive to potentially
threatening stimuli. Studies are underway to look at how people with anxiety
disorders process information. The goal is to see which cognitive capabilities
are affected by anxiety and which are free to handle other information. Data
collected from the studies should help researchers determine more about the
brain pathology associated with anxiety disorders.
Early Life Stress May Play a Role
In animals, NIMH-funded researchers are studying how stress, especially when it
occurs in early life, affects how adverse events are handled later in life. Rat
pups who are subjected to the stress of being separated from their mothers for
several minutes early in life have, months later, a much greater startle
reaction to a stressful event than pups who were never separated. This line of
research may help scientists learn how genes and experience affect who is
vulnerable and who is resistant to anxiety disorders.
Anxiety Disorders and Hormones
Another area of research has led to the discovery that anxiety disorders are
associated with abnormal levels of certain hormones. People with PTSD, for
example, tend to be low on the stress hormone cortisol, but have an
overabundance of epinephrine and norepinephrine, which could be why they
continue to feel anxious after the trauma. In addition, they tend to have
higher-than-usual levels of corticotropin releasing factor (CRF), which switches
on the stress response and may explain why people with PTSD startle so easily.
Scientists are researching ways to correct hormonal imbalances and bring
symptoms under control.
The Importance of Imaging Tools
Scientists may be closer than ever before to creating therapies that are
specifically targeted. NIMH studies use imaging tools to allow researchers to
peer into the living brain and watch the amygdala, the cortex, and other areas
of the brain at work. They can identify abnormal activity when a person has an
anxiety disorder and determine if medication or cognitive and behavioral
therapies help to correct it.
Recent studies of the brain using magnetic resonance imaging showed that people
with OCD had significantly less white matter than did control subjects,
suggesting a widely distributed brain abnormality in OCD.
Imaging studies are also looking at how brain structure may be related to PTSD.
A part of the brain involved in emotion, called the hippocampus, tends to be
smaller in some people with PTSD. NIMH-funded researchers are trying to decipher
whether that is a result of extreme stress responses related to the trauma or
whether people who already have a smaller hippocampus are more prone to PTSD.
NIMH Anxiety Research and Genetics
Research evidence points to genetics as a factor in the origin of anxiety
disorders. Scientists have recently discovered a gene that influences
fearfulness in mice. And NIMH-supported studies of twins have found that genes
play a role in panic disorder and social phobia. Although genes help determine
whether someone will develop an anxiety disorder, heredity alone can't explain
what goes awry. Experience also plays a part. In PTSD, for example, the trauma
is the experience that triggers the anxiety disorder; genetic factors may help
explain why only certain individuals exposed to similar traumatic events develop
full-blown PTSD. Researchers are honing in on the degree of influence that
genetics and experience exert in each of the anxiety disorders—information they
hope will yield clues to prevention and treatment.
Some Cases of OCD Linked to Earlier Infection
NIMH studies of obsessive-compulsive disorder in young people have shown that
the experience of having a streptococcal bacterial infection may lead to the
development of crippling obsessions and compulsions. It appears that a genetic
vulnerability, coupled with rheumatic fever, is associated with some cases of
OCD. Preliminary evidence indicates that special treatment for the infection
improves or cures the OCD.
The Broad NIMH Research Program
In addition to studying anxiety disorders, NIMH supports and conducts a broad
based, multidisciplinary program of scientific inquiry aimed at improving the
diagnosis, prevention, and treatment of other mental disorders. These conditions
include bipolar disorder, clinical depression, and schizophrenia. Increasingly,
the public as well as health care professionals are recognizing these disorders
as real and treatable medical illnesses of the brain. Still, more research is
needed to examine in greater depth the relationships among genetic, behavioral,
developmental, social and other factors to find the causes of these illnesses.
NIMH is meeting this need through a series of research initiatives:
NIMH Human Genetics Initiative
This project has compiled the world's largest registry of families affected by
schizophrenia, bipolar disorder, and Alzheimer's disease. Scientists are able to
examine the genetic material of these family members with the aim of pinpointing
genes involved in the diseases.
Human Brain Project
This multi-agency effort is using state-of-the-art computer science technologies
to organize the immense amount of data being generated through neuroscience and
related disciplines, and to make this information readily accessible for
simultaneous study by interested researchers.
Prevention Research Initiative
Prevention efforts seek to understand the development and expression of mental
illness throughout life so that appropriate interventions can be found and
applied at multiple points during the course of illness. Recent advances in
biomedical, behavioral, and cognitive sciences have led NIMH to formulate a new
plan that marries these sciences to prevention efforts.
While the definition of prevention will broaden, the aims of research will
become more precise and targeted.
More Than 2,000 Grants and Contracts
In total, NIMH supports more than 2,000 research grants and contracts at
universities and other institutions across the nation and overseas. It also
conducts basic research and clinical studies involving 9,000 patient visits per
year at its own facilities on the National Institutes of Health campus in
Bethesda, MD, and elsewhere. NIMH research projects focus on:
basic research on behavior, emotion, and cognition to provide a knowledge base
for a better understanding of mental illnesses
basic sciences, including cellular and molecular biology, developmental
neurobiology, neurochemistry, neurogenetics, and neuropharmacology, to provide
essential information about the anatomical and chemical basis of brain function
and brain disorders
neuroscience and behavioral aspects of acquired immune deficiency syndrome
(AIDS) and behavioral strategies to reduce the spread of HIV (human
immunodeficiency virus)
interventions to treat, prevent, and reduce the frequency of mental disorders
and their disabling consequences
mental health services research, including mental health economics and improved
methods of services delivery
comorbidity among mental disorders and with substance abuse and other medical
conditions, such as depression and heart disease
the prevalence of mental disorders
risk factors for mental disorders
differences in mental health and mental illness among special populations
children and adolescents who suffer from or who are at risk for serious mental
disorders and learning disabilities
psychotherapies and pharmacotherapies for specific disorders
At the beginning of the 21st century, NIMH stands poised to surmount the burden,
loss, and tragedy of mental illnesses that afflict millions of Americans.
Training Future Researchers
The Institute maintains a substantial investment in training and career
development for researchers in fields related to mental health. NIMH is
particularly interested in recruiting clinical investigators trained in
cross-disciplinary areas such as molecular genetics and psychiatry. The
integration of genetics, behavior, and neuroscience will facilitate the
understanding of how the nervous system produces behavior and how behavior maps
onto the brain.
For More Information About NIMH
The Office of Communications carries out educational activities and publishes
and distributes research reports, press releases, fact sheets, and publications
intended for researchers, health care providers, and the general public. A
publications list may be obtained on the Web at http://www.nimh.nih.gov/publist/puborder.cfm
or by contacting:
Office of Communications and Public Liaison, NIMH
Information Resources and Inquiries Branch
6001 Executive Boulevard, Room 8184, MSC 9663
Bethesda, MD 20892-9663
Phone: 301-443-4513
FAX: 301-443-4279
Mental Health FAX4U: 301-443-5158
E-mail: nimhinfo@nih.gov
NIMH home page address:
http://www.nimh.nih.gov
Information about research opportunities at the NIMH Intramural Research Program
may be obtained from:
Office of the Scientific Director, NIMH
9000 Rockville Pike
Building 10, Room 4N224, MSC 1381
Bethesda, MD 20892-1831
Phone: 301-496-3501
Fax: 301-480-8348
Information for scientists on NIMH grants and contracts programs, including
grant application and review, Requests for Applications, Requests for Proposals,
program announcements, research training and career development, small business
programs, program analyses of NIMH extramural research grants and applications,
access to NIH Grants policy, and other material may be obtained from the NIMH
home page: http://www.nimh.nih.gov.
Information about NIMH clinical studies can be obtained by accessing the NIMH
home page at www.nimh.nih.gov or the National Library of Medicine clinical
trials database at www.clinicaltrials.gov.
NIH Publication No. 99-4504
Printed 1999
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