- Cognitive models of post-traumatic stress disorder (PTSD) posit that negative cognitions regarding the self and the world underlie the disorder. In contrast, scarring models — which postulate that distress brings about an elevation in vulnerability — predict the inverse relationship. Both models were tested amongst 156 Israeli trauma victims. Participants were assessed for PTSD symptoms and trauma-related cognitions (negative thoughts regarding self and world) over 2 weeks (T1), 4 weeks (T2), and 12 weeks (T3) following the traumatic event. A cross-lagged structural equation modeling analysis yielded evidence for both cognitive vulnerability and scarring. Baseline PTSD was prospectively associated with an increase in negative cognitions regarding both the self and the world during the T1–T2 period. Negative cognitions regarding the self were prospectively associated with an increase in PTSD symptoms during both T1–T2 and T2–T3 periods. PTSD symptoms and negative cognitions regarding the self thus appear to form a vicious cognitive-symptomatic cycle which might impede recovery.