A number of changes (chemical) have been documented by various researchers, and "emotional addiction" phenomena have been studied by quite a few.

The "fight or flight" reactions seem particularly strong. Most of these probably produce elevations in adrenaline, but there are a number of other hormones and vaguely known "juices" that can participate.

The well-known "brain barrier" generally prevents most of the strange chemicals that slosh around in our bodies from getting to the brain, so that it lives in a fairly "clean" world all its own. One function that has been postulated for adrenaline and associated hormones is that they act as a "transport" mechanism to pass "more" through the brain barrier, much like insulin is the transport link that lets sugars pass from the circulatory system into individual cells and controls how much gets through, but doesn't itself participate much in the metabolism of the cell.

Exactly what "more" gets transported is, so far as I've heard, not really too well known. Several decades ago it was suggested that adrenaline might act as a "super insulin" to raise sugar levels in the brain so that one might react more alertly. I don't know whether that function is supported as a principal function by later work, but even if so it apparently is only one part of what goes on.

One report I recall seeing, from the University of Israel shortly after one or the other of the larger conflicts in the region, claimed to have shown that high "adrenaline" levels (high stress levels) could lead to transport into the brain of chemicals that shouldn't be there and that ordinarily would be excluded by the barrier.

The obvious extrapolation from this is that one reason that US researchers had difficulty accepting the so-called "Gulf War Syndrome" is that when they tested "normal" people (laboratory volunteers) no chemicals got through, while the Israeli researchers suggested that under stress the same chemicals likely would get through to the brain.

Another researcher suggested that this might explain the occurence for a number of drugs of "side effects," largely psychotic, in older patients that don't often occur in younger ones - the old folks, often in care/hospice facilities or controlled by their offspring often are subject to quite a lot of tension, due to having little or no control over their own lives and often being given little information by those caring for them, and this tension may(?) elevate adrenaline or a like compound that promotes transport of some of these drugs into their brains, where the same drugs just don't get there in unstressed subjects. (There are a number of commonly used drugs that dismiss adverse side effects as occuring "only in the aged/senile and feeble minded.")

A friend who has worked for many years with returned veterans has asserted that at least some of them "miss the high" of the fear they felt in the combat zone.

Under threat, when you have a job to do, you have some control over the situation. You can make your preparations to react to the threat, which at least gives the appearance of having some control. Some vets referred to the inability to lose the fear, but now had no way of "facing it," so that they now had the fear but not the high from "doing something" about it via the "get-ready" (response) activities.

The "high" apparently depends quite strongly on being able to react to the situation, so in a more normal environment it's possible that it's the "lashing out response" - or the preparation to do so, or thinking about how you could do so - that is more addictive that just the fear alone.

Anyone who doesn't believe that hate is addictive need only visit one of the "fundy" churches in my area. The entire congregation becomes radiant with joy at the introduction of each new hate object. I've seen it, and it's frightening - even if it's not you they intend to hate next. (They are not the only place where it can be seen, just a very consistent place.)

John