OBJECTIVE: This study indexed the profile of posttraumatic stress disorder (PTSD) after severe traumatic injury to the brain. METHOD: Patients who sustained a severe traumatic brain injury (N=96) were assessed for PTSD 6 months after the injury with the PTSD Interview, a structured clinical interview based on DSM-III-R criteria. RESULTS: PTSD was diagnosed in 26 (27.1%) of the patients. While only 19.2% (N=5) of the patients with PTSD reported intrusive memories of the trauma, 96.2% (N=25) reported emotional reactivity. Intrusive memories, nightmares, and emotional reactivity had very strong positive predictive values for the presence of PTSD. CONCLUSIONS: These findings indicate that PTSD can develop after severe traumatic brain injury. The predominance of emotional reactivity and the relative absence of traumatic memories in patients with PTSD who suffered impaired consciousness during trauma suggest that traumatic experiences can mediate PTSD at an implicit level.