Psychology has slowly incorporated the understanding of the neurobiology-based description of fight-or-flight and it’s importance on the psychological realm of each individual.
Even when the father of psychology (Wilhelm Wundt) had a background of physiology, psychology moved into studying behavior and disconnected from the brain and the body.
Psychology has then connected the fight-or-flight response to stress, since it has a deeper understanding of the phenomenon. Still, most literature about the subject has elaborated over and over what the neurobiologists have explained, without detail into the effect of those types of reactions in the psyche of individuals. Besides fear, psychology has not explained how fight-flight can relate or get triggered by other emotions like shame and guilt. I hope they do soon.
Besides, when we see descriptions of the survival cascade, we read the efforts that scientists make in understanding behavior but use animals for the studies. I wish we could see more studies on the consequences on behavior, perception, and personality of the physiological responses like fight/flight. If psychology goes deeper into the psychological responses, I think it’d be easier to connect personality disorders to trauma.
In any case, the fight-or-flight response on psychology relates to the way people react when under a life-threatening situation, extreme stress, or extreme fear, and it’s recognized as the first stage of a general adaptation syndrome that regulates stress responses. Not much more than that before moving into a pure physiology description of the phenomena.