A systematic review of the scientific literature published between 2014 and 2025 was conducted, focusing on the epidemiology, pathogenetic concepts, and diagnostic approaches to complex post-traumatic stress disorder (CPTSD) in combination with combat-related traumatic brain injury (TBI) among military personnel. The search was performed in international scientometric databases (PubMed/MEDLINE, Web of Science, Scopus, PsycINFO) as well as in national resources, with inclusion of original studies, systematic reviews, and meta-analyses. The findings indicate that although the combination of post-traumatic spectrum disorders with combat-related TBI represents a clinically significant problem, systematically summarized epidemiological data specifically on the prevalence of CPTSD comorbid with combat-related TBI remain limited. The main body of available epidemiological evidence is based on studies of classical PTSD. At the same time, the presence of TBI is associated with an increased risk of developing PTSD compared to military personnel without brain injury. Variability in reported results across the literature is largely explained by differences in methodology, diagnostic criteria, and sample characteristics. It is further emphasized that a key diagnostic challenge is the overlap of symptoms resulting from TBI and the PTSD spectrum, which complicates differentiation between organic and psychogenic components. In the absence of validated specific biomarkers for CPTSD comorbid with TBI, the need for an integrated approach is substantiated, combining neuropsychological, neuroimaging, and clinical-psychopathological assessment. The review concludes with the necessity of unifying diagnostic approaches in accordance with ICD-11 and conducting further research to obtain comparable prevalence estimates and to clarify the mechanisms of comorbidity.