The psychological concept of Repression (the blocking of traumatic memories) is not a real condition. People who suffer trauma have the opposite problem; they are unable to forget the memories that haunt them.
Apparently, the idea arose from psychologists who relied on a formulaic theories of input/output along the lines of, "If the victim has problem X, then they had history Y." The problem with this theory is that people don't necessarily have that history. In this case, the psychologist attempted to "draw out" this memory from the patient's subconscious. Unfortunately, humans are extremely suggestible, and patients were easily persuaded into memories of events that never happened.