Abstract. This study aimed to validate the Type III continuous traumatic stress model assumptions and use it to assess the effect of intersected traumas of civil war and COVID-19 stressors on internally displaced Syrian people. We recruited 891 Syrians from camps (46.5% females, aged 18–90 years [ M = 30.81, SD = 12.04]). We measured COVID-19 stressors, posttraumatic stress disorder (PTSD), complex PTSD (CPTSD), depression, anxiety, and executive functions to assess the variables related to peri-post Type III mental health syndrome. We measured Type I, II, and III traumas and Type III trauma subtypes. To explore the significance of differences between correlation sizes and the comparative severity of each trauma type, we calculated Fisher z scores. We performed path analysis with trauma Types III and II as correlated independent variables and COVID-19 stressors' impact on peri-post Type III trauma mental health syndrome to check their proliferation and impact. Of the sample, COVID-19 had infected 45.9%, 33.1% fit the diagnostic criteria for CPTSD, and 13.9% fit the diagnostic criteria for PTSD. All trauma types were associated with mental health, cognitive deficits, and COVID-19 severity, with a significantly higher association with trauma Type III. Type III-a subtype (intersected discrimination) had the highest associations with each variable. Type III was bidirectionally correlated with Type II and proliferated to Type I traumas (single past events) and COVID-19 stressors, with Type III having a larger effect size on peri-post Type III trauma mental health syndrome. The clinical and conceptual implications of the findings are discussed.