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Combat and Operational Stress Reactions (COSR)

Date of Publication



The physical, emotional, cognitive, or behavioral reactions, adverse consequences, or psychological injuries of Service members who have been exposed to stressful or traumatic events in combat or military operations. COSRs vary in severity as a function of operational conditions, such as intensity, duration, frequency of combat exposure, rules of engagement, leadership, effective communication, unit morale, unit cohesion, and perceived importance of the mission, etc. COSRs do not represent mental health disorders or medically diagnosable conditions and concerns. Post-traumatic stress disorder is not equivalent to or another name for COSR.

Source of Definition

DoD Instruction 6490.05: Maintenance of Psychological Health in Military Operations

Related Glossary Terms

Combat and Operational Stress Control | Combat and Operational Stress Control Consultant | Combat and Operational Stress Control Personnel

Last Updated: December 05, 2018

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