Neurological and Psychological Effects of Combat-Related Stress

The purpose of this study is to determine what is the neurological and cognitive impact of combat exposure and prolonged stress, in the form of service in the Israeli Defense Forces.

Study Overview

• Status: Active, not recruiting
• Conditions: Stress, Psychological; Stress Disorder, Posttraumatic
• Intervention / Treatment: Other: Combat Exposure

Detailed Description

Attention biases in threat processing have been assigned a prominent role in the etiology and maintenance of anxiety disorders. This study aimed to characterize the mental resilience of combat soldiers, and explore the neuro-cognitive impact of prolonged stress, using eye-tracking, MRI and fMRI measurements. Participants will be assessed using questionnaires, cognitive tasks and magnetic imaging at 5 timepoints over the span of 4 years. Outcome measures will be depression, anxiety and post-traumatic scores, as well as dwell time on threat in eye-tracking paradigms tested in previous studies, and blood oxygen level-dependent (BOLD) signals in magnetic resonance imaging (MRI) measurements.

• Study Type: Observational
• Enrollment (Actual): 100

Contacts and Locations

Study Locations

• Israel
  • Tel Aviv, Israel, 69978
    • Tel Aviv University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 23 years (Adult)
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

Healthy 18-year-old Israeli males.

Description

Inclusion Criteria:

• Soldiers in the paratroopers brigade or students in Tel-Aviv University;
• A signed consent form;
• Hebrew native speakers.

Exclusion Criteria:

• A diagnosis of a neurological disorder (i.e., epilepsy, brain injury);
• Drug or alcohol abuse;
• Cannot undergo an MRI scan, due to metal implants or other metallic foreign bodies, claustrophobia, large tattoos or irremovable piercings;
• Require glasses with a number greater than 7;
• A diagnosis of psychotic or bipolar disorders.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Soldiers; 50 Israeli Defense Forces (IDF) infantry soldiers, all male, aged 18 years, with Hebrew as the dominant language and no condition excluding an MRI scan.	Other: Combat Exposure; Soldiers will be exposed to combat as part of their routine military service. The ROTC students will not be exposed to combat.
Students; 50 Reserve Officer Training Corps (ROTC) undergraduate students at Tel-Aviv University, all male, aged 18-19, with Hebrew as the dominant language and no condition excluding an MRI scan.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline - PTSD Checklist for DSM-5 (PCL-5) score	PCL is questionnaire assessing posttraumatic stress disorder symptoms. It contains 20 items on a severity scale of 0-4, measuring the existence and severity of post-traumatic symptoms. The minimal score, indicating no post-traumatic stress, is 0. The maximal score is 80, indicating extremely severe post-traumatic stress.	4 years, from time point 1 to time point 5
Neurological measures - Gray matter volume	Gray matter volume, i.e. the density of brain cells in a particular region (outcome to be measured in cm3), to be derived from the MRI scans, and compared between the two groups across the various time points.	4 years, from time point 1 to time point 5
Neurological measures - Functional connectivity	Functional connectivity, indicating the level of synchronous activity of certain brain regions during rest (temporal correlation is usually expressed as a Pearson's r); Also to be derived from the MRI scans, and compared between the two groups across the various time points.	4 years, from time point 1 to time point 5
Neurological measures - Structural connectivity	Structural connectivity between regions of the brain (Diffusivity is measured as 10-3mm2.s-1) and the properties of the white matter (expressed with Diffusion tensor imaging (DTI) measures, mainly Fractional Anisotropy (FA) and Mean Diffusivity (MD)); Also be derived from the MRI scans, and compared between the two groups across the various time points.	4 years, from time point 1 to time point 5
Neurological measures - Task activations	Task activations, and specifically the areas activated during the dot-probe task, and how they change over time (expressed as the level of the BOLD signal strength change during the task). To be derived from the MRI scans, and compared between the two groups across the various time points.	4 years, from time point 1 to time point 5

Collaborators and Investigators

• Sponsor: Tel Aviv University
• Collaborators: Medical Corps, Israel Defense Force
• Investigators: Principal Investigator: Yair Bar-Haim, PhD, Tel Aviv University

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2019
• Primary Completion (Estimated): March 1, 2025
• Study Completion (Estimated): March 1, 2025

Study Registration Dates

• First Submitted: November 24, 2020
• First Submitted That Met QC Criteria: December 2, 2020
• First Posted (Actual): December 3, 2020

Study Record Updates

• Last Update Posted (Actual): April 16, 2024
• Last Update Submitted That Met QC Criteria: April 14, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Behavioral Symptoms; Mental Disorders; Trauma and Stressor Related Disorders; Stress Disorders, Traumatic; Stress Disorders, Post-Traumatic; Stress, Psychological
• Other Study ID Numbers: TAUatm

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No