this ill depends on ormons. when we are in a stressing situation, our organism reacts producing more ormons to face the emergency. but when the stress is very hard or very long, or both, the mechenism of the production of ormons can be altereted. these are facts.
think that the neuronal connections are for more than the 80% made by ormons (and not by electricity), and that neuronal, endochrinal and immunytal
systems are a unique net of ormons.
in fact, for exemple, i suffer of losses of memory, of the addison ill, of ipothyroidism, etc etc.
i could suggest you some scientific pubblications i read, but they are in italian. but surely. if you search for "ipothalam-ipofisis-thyroides axes", you will surely find what i am talking about.
take care!
ps. sorry for my english!