Recruiting

Observational Study

Sponsor:

The University of Texas Health Science Center, Houston

Code:

NCT04770584

Conditions

Post Traumatic Stress Disorder

Eligibility Criteria

Sex: All

Age: 18 - 70

Healthy Volunteers: Accepted

Interventions

Fear Conditioning

Avoidance conditioning

Pavlovian fear extinction learning

Willingness to pay to avoid shock

Study Details

Brief summary:

The purpose of this research study is to study how the brain learns to avoid certain stimuli or situations using an experimental paradigm. The big goal is to measure brain responses and subject's feelings and expectations when they are learning to actively avoid experimental stimuli, and how fear extinction learning and monetary cost can change how and when subjects are to avoid.

Conditions

Post Traumatic Stress Disorder

Study ID

NCT04770584

Start date

Sep 9, 2021

Status verified date

Apr, 2026

Completion date

Jan, 2028

Anticipated

Primary completion date

Jan, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 70

Healthy Volunteers: Accepted

Inclusion Criteria:

1. 18 - 70 years of age
2. Female or Male
3. Inclusion Criteria: PTSD Subjects

a. Diagnosis of current PTSD
4. Inclusion Criteria: Trauma-exposed healthy controls (TEHC)

1. SCID diagnosis consistent with no current psychiatric disorders, and no current PTSD
2. History of trauma exposure
5. Inclusion Criteria: Healthy controls (HC)

1. SCID diagnosis consistent with no current psychiatric disorders ("Axis I" disorders).
2. No history of trauma exposure
6. Willing and able to provide informed consent.

Exclusion Criteria for ALL subjects:

1. History of neurologic disease (e.g. tic disorder)
2. Current significant suicidal ideation, plan or intent or suicidal behavior in past 6 months based on CSSRS or Self-injurious behavior that involves suicidal intent, requires medical attention, or occurs daily
3. History of seizure or significant head trauma
4. History of the serious/significant psychiatric diagnosis ("Axis I" disorders)
5. Use of neuroleptics within one year prior to study
6. Current substance use (assessed by urine toxicology; positive urine toxicology screen for any substance, with the exception of THC). Per PI judgement and approval: if urine toxicology is positive for a substance, participant may be eligible to proceed with study provided their urine toxicology (or saliva test for THC) is negative at experimental visit(s)
7. Pregnancy (to be ruled out by urine ß-HCG)
8. Metallic implants or devices contraindicating magnetic resonance imaging
9. High risk of adverse emotional or behavioral reaction, and/or an inability to understand study procedures or the informed consent process

Additional exclusion criteria for Trauma-exposed healthy controls (TEHC) group and Healthy controls (HC) group:
10. Current psychiatric diagnosis ("Axis I" diagnoses)

Study Design

Enrollment

300 participants

Anticipated

Intervention Model

Single group

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Emotional learning paradigm

After the initial screening / baseline assessment visit, participants will undergo two Experimental Visits, which include participation in an emotional learning paradigm and an fMRI scan over the course of two consecutive days. Participants will be asked to look at pictures on a computer screen to measure physiological response physiological response (skin conductance response) and brain responses using a functional Magnetic Resonance Imaging (fMRI) machine. These two visits will be scheduled within a month from the baseline assessment visit.

Interventions

Fear Conditioning

Participants will be administered increasing intensities of mild electric shock via electrodes connected to the foot. New Biopac stimulators that can deliver higher shock intensity, provided participants agreement will be used to assure adequate conditioning levels. Stimulation is measures in milliamps (mA), and each delivered stimulation will be 0.5 seconds long (500 milliseconds). To colored (blue, red, \& yellow) light stimuli (CS). The light stimulus is followed by a shock or no shock depending on color.

Avoidance conditioning

Via button pressing. Only one stimulus-CS will enable control over experiencing the shock: the participant can press the button during the first 2 seconds of the light presentation to avoid the shock.

Pavlovian fear extinction learning

After avoidance conditioning, the CS+ associated with avoidance responding appears with no button to press and no shock is administered.

Willingness to pay to avoid shock

On the next day, participants receive a monetary stipend to use to pay to guarantee that they are not to receive any shocks if they press a button from the CS+. This and all previously described experimental phases noted above will occur inside of the fMRI scanner.

Primary outcome measure

  • Skin Conductance Response (SCR) [ Time Frame: Experimental Day 1, Experimental Day 2 ]
  • Functional MRI (fMRI) responses [ Time Frame: Experimental Day 1, Experimental Day 2 ]

Central Contacts and Locations

Central contacts

Mohammed Milad, PhD

713-486-2754Mohammed.R.Milad@uth.tmc.edu

Locations

UTHealth Houston

Recruiting

Houston, Texas, United States, 77054

Contacts

Mohammed R. Milad, PhD

Mohammed.R.Milad@uth.tmc.edu

More Information

Sponsor

The University of Texas Health Science Center, Houston

Last update posted

May 5, 2026

Last verified

Apr, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by The University of Texas Health Science Center, Houston on 2026-05-05.