The memory of the trauma acts like a splinter in the mind – it is the body’s reaction to the foreign body that becomes the problem, not the object itself.
From a neuroscience perspective, imaging studies of the brains of trauma patients usually show abnormal activation of the insula. The insula integrates and interprets information from sensory organs and sends fight-or-flight signals to the amygdala as needed.
In people with trauma, these signals fire all the time. It doesn’t require any conscious influence – you just feel irritable all the time, for no apparent reason. You may feel that something has gone wrong, or that disaster is imminent. These strong feelings are generated deep in the brain and cannot be removed by reason or intellect.