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NCT Number: NCT01477762

Cortisol Suppression and Startle Responses in Posttraumatic Stress Disorder (PTSD)

Posttraumatic stress disorder (PTSD) occurs in some people after exposure to events that cause extreme fear or helplessness. The incidence of war zones worldwide and the prevalence of violence in large cities in the U.S., increases the likelihood that people will experience a traumatizing event in their lifetime. About 1 in 10 people who survive such events will develop PTSD, while most people will get better over time. This suggests that some people may have biological vulnerabilities that make it harder for them to recover. One of these biological risk factors may be related to how stress hormones work in people who get sick. Another is how people react to things that make them afraid or nervous, investigators have found that PTSD patients have higher than normal fear reactions. The part of the brain that reacts to fearful stimulation is linked to stress hormones; the purpose of this study is to examine how these systems interact. The study will suppress stress hormones (cortisol) production in one group of participants, while another will get a placebo. When their cortisol is suppressed, the participants will undergo a startle study to see if their fear responses are decreased. Investigators expect that people PTSD will show a normal fear response when their cortisol levels are reduced, similar to people without PTSD. This research can help discover new medicines for people with PTSD.

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Key information

Conditions

Post Traumatic Stress Disorder Mental Disorders Stress Disorders, Post-Traumatic Stress Disorders, Traumatic Trauma and Stressor Related Disorders

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Grady Health System

Atlanta, Georgia, 30303, United States

About this study

The proposed study will provide innovative tools to tease apart the relationship between amygdala-dependent neurophysiology and HPA-axis sensitivity in a human clinical population. Investigators have discovered that cortisol suppression reduces fear responses in PTSD coupled with the development of new fear conditioning paradigms, providing a unique opportunity to interrogate amygdala-HPA interactions to determine aspects of the neurobiological underpinnings of PTSD-related pathology.

Aim 1a will examine baseline and fear-potentiated startle (FPS) response, as well as cognitive awareness in PTSD patients and traumatized Non-PTSD controls during a fear conditioning experiment 10 hours after dexamethasone administration in a double-blind, placebo controlled crossover design.

Aim 1b will examine the above outcome measures in PTSD patients and controls during a fear conditioning experiment 1 hour after dexamethasone administration in order to control for direct effects of dexamethasone.

Aim 2a will examine fear-potentiated startle (FPS) response in PTSD patients and traumatized Non-PTSD controls during fear extinction, when the fear is acquired 10 hours after dexamethasone administration in a double-blind, placebo controlled crossover design.

Aim 2b will examine the same outcome measures in PTSD patients and controls, when the fear is acquired 1 hour after dexamethasone administration in order to control for direct effects of dexamethasone.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Able to give informed consent
  • Willing to participate in initial assessment and 2 full days of interviews and imaging visit
  • Able to understand English and no obvious deficit in comprehension or following directions
  • 18-65 years old

Exclusion criteria

  • Mental Retardation (per clinical judgment of study physician)
  • Psychotic Disorder (per clinical judgment of study physician)
  • Acute suicidal ideation
  • Pregnancy
  • Positive urine drug screen
  • Active medical disorders contributing to psychiatric sx e.g. hypo or hyperthyroidism, SLE, advanced cirrhosis, etc. (per clinical judgment of study physician)

Treatment and study plan

Dexamethasone

Drug

One tablet of 0.5 mg dexamethasone will be taken ten hours prior to completing study assessments.

Placebo

Drug

One placebo tablet will be taken ten hours prior to completing study assessments.

Primary outcomes

  1. Mean Baseline Startle Magnitude During Fear Conditioning

    Time frame: 10 hours after drug administration

    The study measured the acoustic startle response magnitude to a sudden noise using electromyography of the eyeblink muscle. This response magnitude was used as the individual's baseline to compare to the startle magnitude to the danger signal to see if fear conditioning had occurred.

  2. Mean Startle Magnitude to Danger Signal During Fear Conditioning

    Time frame: 10 hours after drug administration

    The acoustic startle response magnitude was measured using electromyography recordings of the eyeblink muscle when a sudden tone was delivered through headphones in the presence of a stimulus that was paired with an aversive outcome (i.e. the danger signal). If an individual showed successful fear learning, then startle to the danger signal would be greater than baseline startle.

  3. Mean Fear-potentiated Startle to Danger Signal During Early Extinction

    Time frame: 10 hours after drug administration

    Fear-potentiated startle was measured as a difference score between the startle to danger signal and the baseline. This difference score reflects the degree of fear response at the beginning of extinction.

  4. Mean Fear-potentiated Startle to Danger Signal During Late Extinction

    Time frame: 10 hours after drug administration

    This measures the level of fear-potentiated startle (the difference between startle magnitude to the danger signal and baseline startle magnitude) at the end of extinction. Because the danger signal is no longer paired with the aversive stimulus like it was during the conditioning phase, the fear response should decrease from early to late extinction in individuals who show intact extinction learning.

Sponsors and collaborators

Lead sponsor

Emory University

Other

Collaborators

  • National Institute of Mental Health (NIMH)

Registry information

Official study title

Effects of Cortisol Suppression on Fear-Potentiated Startle in Traumatized Individuals With and Without PTSD

Acronym: CSS

Important dates

Study start
2011
Primary completion
2015
Study completion
2015
First posted
Nov 23, 2011
Registry last updated
Apr 18, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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