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Effects of Arousal and Stress in Anxiety

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ClinicalTrials.gov Identifier: NCT00026559
Recruitment Status : Completed
First Posted : November 12, 2001
Last Update Posted : August 4, 2022
Information provided by (Responsible Party):
National Institutes of Health Clinical Center (CC) ( National Institute of Mental Health (NIMH) )

Brief Summary:

This study has several parts. One part will examine the influence of factors such as personality and past experience on reactions to unpleasant stimuli. Others will examine the effect of personality and emotional and attentional states on learning and memory.

When confronted with fearful or unpleasant events, people can develop fear of specific cues that were associated with these events as well as to the environmental context in which the events occurred via a process called classical conditioning. Classical conditioning has been used to model anxiety disorders, but the relationship between stress and anxiety and conditioned responses remains unclear. This study will examine the relationship between cued conditioning and context conditioning . This study will also explore the acquisition and retention of different types of motor, emotional, and cognitive associative processes during various tasks that range from mildly arousing to stressful.

Condition or disease Intervention/treatment Phase
Healthy Volunteers Device: Shock Device Device: Auditory Startle Device Not Applicable

Detailed Description:

Objective: Fear and anxiety are adaptive responses to different types of threats. Fear is a short-duration response evoked by explicit threat cues and anxiety a more sustained state of apprehension evoked by unpredictable threat. This protocol studied fear using Pavlovian fear conditioning in two studies. Studies 1 and 3. Study 2 focused on anxiety. Studies 1 and 3 will be discontinued to focus uniquely on the study of anxiety. Specifically, we will examine the interactions between anxiety induced experimentally using verbal threat and cognitive processes. We will seek to 1) characterize the effect of anxiety on key cognitive processes including working memory and attention control and 2) examine the extent to which performance of cognitive tasks distract from anxiety.

Study population: This more-than-minimal-risk protocol will test medically and psychiatrically healthy volunteers aged 18-50. Pregnant or nursing women will be excluded.

Method: Fear and anxiety will be measured using the startle reflex to brief and loud sounds. Fear conditioning will be assessed using shock as unconditioned stimulus. Cognitive performance will be examined during periods of unpredictable shock anticipation.

Outcome measures: The study will include cognitive performance and measure of aversive states, primarily the startle reflex.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 1530 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Effects of Arousal and Stress on Classical Conditioning
Actual Study Start Date : January 10, 2001
Actual Primary Completion Date : July 28, 2022
Actual Study Completion Date : July 28, 2022

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Anxiety Shock

Arm Intervention/treatment
Experimental: Threat Conditions
threat of shock and auditory startle
Device: Shock Device
Shock Device

Device: Auditory Startle Device
Auditory Startle Device

Primary Outcome Measures :
  1. Startle Reflex [ Time Frame: study visit ]
    startle reflex

  2. Performance on cognitive tasks [ Time Frame: study visit ]
    performance on cognitive tasks

Secondary Outcome Measures :
  1. Cognitive tests [ Time Frame: during study visit ]
    performance on standard cognitive tests (e.g. working memory capacity

  2. psychological questionnaires [ Time Frame: during study visit ]
    psychological questionnaires (Spielberger state and trait anxiety)

  3. Skin conductance [ Time Frame: during study visit ]
    Skin conductance

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
  • Males and females
  • Age 18-50


  • Pregnancy
  • Any current ongoing medical illness
  • Current Axis I disorders
  • Past significant psychiatric disorders (e.g., psychotic disorders) according to DSM-IV
  • Current alcohol or substance abuse according to DSM-IV criteria
  • History of alcohol or substance dependence based on DSM-IV criteria within 6 months prior to screening
  • Current psychotropic medication use
  • Current or past organic central nervous system disorders, including but not limited to seizure disorder or neurological symptoms of the wrist and arms (e.g., carpal tunnel syndrome). The latter exclusion is for shock studies only.
  • Positive urine toxicology screen
  • Employees of NIMH or an immediate family member of a NIMH employee.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00026559

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United States, Maryland
National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Institute of Mental Health (NIMH)
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Principal Investigator: Monique Ernst, M.D. National Institute of Mental Health (NIMH)
Additional Information:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

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Responsible Party: National Institute of Mental Health (NIMH)
ClinicalTrials.gov Identifier: NCT00026559    
Other Study ID Numbers: 010185
First Posted: November 12, 2001    Key Record Dates
Last Update Posted: August 4, 2022
Last Verified: July 28, 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Plan Description: .We will provide de-identified data to repositories but no identifiable data.

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: Yes
Keywords provided by National Institutes of Health Clinical Center (CC) ( National Institute of Mental Health (NIMH) ):
Classical Conditioning
Fear Conditioning
Normal Volunteers
Healthy Volunteer
Normal Control