Amnesia for traumatic events among recent survivors: a pilot study.

Objective: Traumatic amnesia has been amply documented in the psychoanalytic literature but inconsistently in the research literature.
Method: Six trauma were followed prospectively. Survivors were interviewed 7, 30, and 120 days following the traumatic event. Each interview documented in detail their recollections of the day of their trauma.
Results: In four subjects who did not develop posttraumatic stress disorder (PTSD), we found brief, stable, and persistent memory gaps, which coincided with the moment of greatest emotional intensity. In two subjects who developed PTSD, we found, in addition to the previous form of amnesia, longer, progressive, and unstable memory gaps.
Discussion: Neurobiological research offers two explanatory mechanisms for the observations: A failure of acquisition of episodic memories may account for the stable deficits seen in all subjects. This could coincide with stress-induced malfunction of the hippocampal declarative memory system. A failure of spontaneous recall may account for the more extended traumatic amnesia that was observed in PTSD patients. This resembles the psychoanalytic description of repression.
Conclusion: These preliminary findings suggest that brief, irreversible memory gaps are common in trauma survivors, whereas longer, progressive, and potentially reversible amnesia occurs among survivors who develop PTSD.