The research goal is to uncover the neurocognitive moderators of PTSD trajectories, by documenting clinical symptoms, cognitive functioning, and brain structure and function, one-, six- and fourteen months following a traumatic event, in a large population of survivors at initial high risk for PTSD.

Inclusion Criteria:

• Age 18 - 65 years
• Able to read and comprehend Hebrew
• Arrived in the ER because of one of the following: car accidents, terrorist attacks, work accidents, home accidents, burns, physical assault, large-scale disaster.

Exclusion Criteria:

• Individuals with known claustrophobia
• Individuals with history of substance abuse
• Individuals with current or past psychotic or bipolar I disorder
• Individuals with chronic PTSD at the time of the current trauma
• Individuals on psychotropic medication or recreational drugs in the week that precedes the MRI
• Individuals with hearing problems
• Individuals with head trauma with coma exceeding 30 minutes
• Individuals which can't perform MRI due to safety reasons (e.g. irremovable metals in their body)

Adult civilians admitted to Tel-Aviv Sourasky Medical Center's Emergency Room (ER), following a potentially traumatic incident. The initial screening will be done via telephone-based structured interviews within 10 days of ER admission, in order to confirm the occurrence of psychologically traumatic event, identify & assess those expressing initial Acute Stress Disorder (ASD) symptoms.