<human>: Provide a brief overview of the text.

A friend of mine is seeking treatment for an anger/rage disorder.  Apparently he's been dealing with it for years and it's started getting progressively worse.  I knew he lost his temper every once in a while, but it wasn't until he started describing it that I thought there might be something more to it.

Here is how he described the symptoms to me:

>It starts with being mad at something, and often it is nothing to get that upset over. Then, my temper flares and I begin to get a kind of tunnel vision. It starts with a black ring around my field of vision and eventually goes almost completely black. At that point I can tell I am doing something that I shouldn't, but it's like I'm watching a dream or something. Kind of an out of body experience where I am watching what is going on, knowing it is wrong but I can't make it stop. After it is done, I am usually emotionally depleted for several days. 

I did a bit of searching for this and I found at least one other person who describes this black ring of anger.  There is one poster [here about halof way down] who also talks about this black ring in field of vision.  Worth noting that my friend doesn't get violent (to the best of my knowledge).

He's seeking treatment, which I think is the right move.  But I know that sometimes people can spend months or years trying to find a practitioner who knows the cause of the problem.  Like someone with Lupus or Celiac Disease... I don't want this guy to go around undiagnosed if this is just something obscure.  On the other hand, maybe what he's experiencing is just adrenaline and he's just got a problem controlling his temper.  Entirely possible.
<bot>: my friend loses his temper and reports seeing a black ring around his field of vision until it all goes to black.  Does anybody know if there is a specific name for this type of disorder?