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Completed

NCT Number: NCT04651192

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.

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Key information

Conditions

Stress Disorder, Posttraumatic Behavior Behavioral Symptoms Mental Disorders Stress Disorders, Post-Traumatic Stress Disorders, Traumatic Stress, Psychological Trauma and Stressor Related Disorders

Age range

18 year–23 year

Sex eligibility

Male

Study type

Observational

Primary location

Tel Aviv University

Tel Aviv, 69978, Israel

About this study

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.

Who can participate

Healthy volunteers accepted: No

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

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.

Treatment and study plan

Combat Exposure

Other

Soldiers will be exposed to combat as part of their routine military service. The ROTC students will not be exposed to combat.

Primary outcomes

  1. Change from baseline - PTSD Checklist for DSM-5 (PCL-5) score

    Time frame: 4 years, from time point 1 to time point 5

    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.

  2. Neurological measures - Gray matter volume

    Time frame: 4 years, from time point 1 to time point 5

    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.

  3. Neurological measures - Functional connectivity

    Time frame: 4 years, from time point 1 to time point 5

    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. Neurological measures - Structural connectivity

    Time frame: 4 years, from time point 1 to time point 5

    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.

  5. Neurological measures - Task activations

    Time frame: 4 years, from time point 1 to time point 5

    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.

Sponsors and collaborators

Lead sponsor

Tel Aviv University

Other

Collaborators

  • Medical Corps, Israel Defense Force

Registry information

Important dates

Study start
2019
Primary completion
2025
Study completion
2025
First posted
Dec 3, 2020
Registry last updated
May 28, 2025

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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