Trauma
The significant impact of a negative experience on our mind that can be revisited, not as one recalls a memory of a past event, but a literal reliving of that moment, over and over again, in one's mind as though it were happening in the present. time is a flat circle.
The things that cause trauma are as personal as our fingerprints. There are certainly things statistically more likely to be experienced as traumatic than others, like a horrible injury or witnessing someone's sudden death, but the experiences that traumatize us are ours, both in what happened and how it can be triggered, like a permanent bruise on the memory.
He drew a diagram, a meandering life line, and began plotting noughts and crosses along it — the former being “good” events; the latter “bad”. Attached to the life line, to an internal narrative, these events were ordered and organised. Trauma, however, is a free-floating cross, he said. Though we might be able to plot the event on a line in theory, the emotional response to that experience can return and re-establish itself, front and center, in the present, by attaching itself to other experiences that may trigger it.
-- Xenogothic