Prevalence of Complex Post-Traumatic Stress Disorder (CPTSD): A Systematic Review and Meta-Analysis.

This systematic review and meta-analysis aimed to assess complex post-traumatic stress disorder (CPTSD) pooled prevalence across global and specific populations (e.g., military, clinical) and examined potential gender differences. We systematically searched five major databases (Web of Science, Scopus, PsycNET, Psych and behavioural sciences collection, PubMed) up to 31/01/2025 for peer-reviewed articles reporting CPTSD prevalence using validated ICD-11 assessments. Articles were assessed for quality using the JBI prevalence checklist; no studies were excluded. In total 138,681 participants from 167 studies were analysed. Gender-specific analyses were conducted where prevalence was reported by gender. A random-effects model with the meta package in R estimated the global pooled prevalence of CPTSD at 6.2 % (95 % CI [3.7 %, 10.3 %]). Prevalence varied across specific trauma-exposed population groups; highest in clinical (44.7 %), domestic violence/sexual abuse survivors (40.0 %), and military (36.4 %) samples, and lowest in emergency services (7.4 %). No gender difference in prevalence was observed. Findings suggest the support systems or selection processes inherent in emergency services may lower CPTSD risk. Conversely, extreme trauma, limited support, or cultural factors may explain elevated prevalence in military samples. High CPTSD prevalence in clinical samples highlight trauma's pervasive impact, underscoring the need for targeted treatment addressing both CPTSD and comorbidities (e.g., mood, anxiety disorders). The absence of gender differences contrasts with typically higher PTSD rates in women. Limitations include inconsistent trauma definitions and lack of clinician-administered instruments. Findings highlight the need for standardised data collection and reporting, gender-specific reporting, and recognition of CPTSD as a comorbidity in clinical settings.