The stress response releases glucose to energize us to “fight or flight” from a perceived danger. Too much stress can shut down our systems and cause Chronic Fatigue Syndrome. Early stress can impair the HPA axis and cause us to feel charged up even though we cannot identify a trigger. These are the concepts that I want to convey to my students. The problem is that we know so little. There is a developing system which is programmed to help us cope with perceived danger, however, when this system is injured in early childhood, our sense of perceived danger and/or our reaction to it may be seriously impaired, resulting in either an unnecessary hypervigilence or an overwhelming sense of collapse. Perhaps medication can press the re-set button, but we are a long way from knowing that, except to say certain patients have that experience. The below cited New York Times article speaks to the complexity of this circuit. We know a little, allowing us to once again have more questions than answers.
https://en.wikipedia.org/wiki/Hypothalamic%E2%80%93pituitary%E2%80%93adrenal_axis