| City: |
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Bethesda |
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State:
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MD |
| Zip Code: |
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20892 |
| Conditions: |
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Anxiety Disorders |
| Purpose: |
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Fear and anxiety are normal responses to a threat. However, anxiety is considered abnormal
when the response to the threat is excessive or inappropriate. This study will examine
changes in the body and brain that occur during unpleasant learning experiences in healthy
volunteers with high, moderate, and low levels of anxiety.
A high degree of generalized anxiety is a component of many anxiety disorders and is
regarded as a marker of vulnerability for these disorders. People with anxiety disorders and
individuals with high degrees of anxiety have inappropriate expectations of unpleasant
events. This study will investigate the development of expecting unpleasant events in
healthy volunteers with varying degrees of anxiety using aversive conditioning models. A
later phase of the study will enroll participants with anxiety disorders and compare their
responses to those of healthy volunteers.
Healthy volunteers who have no history of psychiatric or major medical illness will be
enrolled in this study. Volunteers will come to the NIH Clinical Center three times for
outpatient testing.
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| Study summary: |
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High-generalized anxiety is a concomitant of many anxiety disorders and is often regarded as
a vulnerability marker for these disorders. One characteristic of patients with anxiety
disorders and high trait-anxious individuals is inappropriate expectancies of aversive
events. The overall aim of the present protocol is to investigate mechanisms that may
promote the development of these aversive expectancies using expectancy-based,
associative-learning models.
During aversive conditioning in which a phasic explicit-cue (e.g., a light) is repeatedly
associated with an aversive unconditioned-stimulus (e.g., a shock), the organism develops
fear to the explicit cue as well as to the environmental context in which the experiment
took place. We have obtained preliminary evidence suggesting that contextual fear
represents aspects of aversive states that are central to anxiety disorders. In this
protocol, we seek further evidence for the relevance of contextual fear to mood anxiety
disorders.
One important determinant of contextual fear in both humans and animals is predictability:
contextual fear increases when aversive events (e.g., electric shock) are unpredictable, as
opposed to when they are predictable. The present protocol will examine the role of
predictability of aversive states and of conditioning on threat appraisal in anxious
individuals.
A second aim is to examine processes that may promote the development of contextual fear.
Classical aversive-conditioning is an ideal technique to explore cognitive, attentional, and
emotional processes underlying the development of aversive expectations to explicit and
contextual cues. We will attempt to relate conditioned performance to measures of 1)
autonomic reactivity (orienting response and heart-rate variability) and 2) attentional
bias. Substantial evidence suggests that autonomic reactivity has broad implication for
cognitive and affective regulation and that attentional biases may imply a role in
generating and/or maintaining maladaptive levels of anxiety.
A third aim is to use socially-relevant stimuli to examine fear and anxiety in social
anxiety disorders. These include a speech stressor given in a virtual reality environment
and using faces as conditioned stimuli and social words in a classical conditioning
experiment.
Finally, given the high comorbidity between anxiety and depression, a last aim is to examine
the role fo depression on these measures of fear and anxiety. |
| Criteria: |
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- INCLUSION CRITERIA FOR BOTH PATIENTS AND HEALTHY CONTROLS:
- Currently the study sample will consist of healthy subjects without a current or past
history of psychiatric or major medical illness.
- Following implementation of an appropriate plan to care for psychiatric patients,
this protocol will include patients with a primary diagnosis of generalized anxiety
disorder, panic disorder, SAD, PTSD, specific phobia and major depression according
to DSM-IV.
- All subjects will be between 18 and 60 years old.
- Male and female subjects will be included.
- All subjects must be able to give written informed consent prior to participation in
this study.
- All eligible subjects must be in good physical health as confirmed by a complete
physical exam (including normal vital signs), electrocardiogram and neurological
exam, and routine lab tests of blood and urine.
EXCLUSION CRITERIA FOR HEALTHY SUBJECTS:
- Female subjects who are currently pregnant
- Subjects who meet DSM-IV criteria for alcohol and/or substance abuse or substance
dependence within 6 months prior to screening
- Current or past Axis I psychiatric disorders as identified with the Structured
Clinical Interview for DSM-IV-TR axis disorders, non-patient edition (SCID-np);
- History of any disease, which in the investigators' opinion may confound the results
of the study, including, but not limited to, history of organic mental disorders,
seizure, or mental retardation;
- Subjects who take psychoactive medications or medications that can interfere with the
study;
- Medical or neurological illnesses likely to interfere with the study;
EXCLUSION CRITERIA FOR PATIENTS:
- Patients who would be unable to comply with study procedures or assessments;
- Female patients who are currently pregnant;
- Specific phobia patients carrying a diagnosis of generalized anxiety disorder;
- Patients who meet DSM-IV criteria for alcohol and/or substance abuse or substance
dependence within 6 months prior to screening;
- Patients who are currently on psychotropic medications with the exception that PTSD
patients currently taking SSRI's, benzodiazepines, or tricyclic antidepressants will
be included. (Patients who are required to be free of all psychotropics must be off
medication for 2 weeks, 6 weeks for fluoxetine. Additionally, PTSD patients on
psychotropics other than SSRI's, benzodiazepines, or tricyclic antidepressants must
be off medication for 2 weeks prior to testing. Patients will not be taken off
medications for the purpose of the study);
- Patients who are on a medication that may interfere with the study;
- Medical or neurological illnesses likely to interfere with the study;
- Patients will be excluded if they have a current or past history of any psychotic
disorder, bipolar disorder, delirium, dementia, amnestic disorder, cognitive disorder
not otherwise specified, any of the pervasive developmental disorders, or mental
retardation |
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| Study is available at: |
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National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, MD 20892
United States
Primary Contact:
Patient Recruitment and Public Liaison Office
Email: prpl@mail.cc.nih.gov
Phone: (800) 411-1222 |
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If you are interested in this clinical trial please use the contact information above. If you would like to get additional information about this clinical trial please visit ClinicalTrials.gov.
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| Data Source: |
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ClinicalTrials.gov |
| Date Processed: |
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March 21, 2011 |
Modifications to
this listing: |
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Only selected fields are shown, please use the link
above to view all information about this clinical trial. |
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