The purpose of the research work is the theoretical and empirical analysis of the study of the nature of combat stress in military personnel and the assessment of psychotherapeutic methods of providing psychological assistance in extreme situations. The authors used the following methods to achieve this goal: method of analysis and synthesis, hermeneutic method, testing method, comparative method, and generalization method. The results of the research work have revealed the meaning of traumatic stress, psychological trauma, and combat mental trauma, and explained the concept of combat stress and the dynamics of its growth. The findings identified the factors of posttraumatic stress syndrome and its prevalence, tracked down the dynamics of psychoemotional disorders, and revealed the importance of military psychological selection and determination of combat readiness. The authors established the main tasks of a staff psychologist in working with military personnel, conducted an empirical study of the nature of combat stress in the military, observed main psychotherapeutic tools for the prevention of negative mental states in combat conditions, and investigated self-regulation techniques of emotional, physical, and mental health. The practical significance of the scientific work lies in the modern coverage of the phenomenon of combat stress and the classification of effective psychotherapeutic methods that will ensure the sustainable psychological preparation of the soldiers for extreme situations.