I've just recently tried to formulate a life history interview technique that tries to look at rage.
I get some help from WS in this, as we are all pondering it. There seem to be two uses of the word. One is "blind" rage, in which the rage-experiencer states that they literally blacked out, can remember up to a certain point in time, and then everything is just red or black blur in their mind after that. These are statements from people who know they committed a crime and remember the lead-up, but at some point, lost their minds and did something they did not specifically plan to do at that moment (they've usually thought about hurting people, frequently). MMPI and other personality tests do ask about such dark thoughts - many people have them, at least occasionally, if they are honest. A mild example would be wishing you could grab that parking space by speeding up in your car when someone else is coming from the wrong direction to get to "your" space, and you don't care if you hit them, you're so mad! (That's not rage, if you simply went and found another spot, IMO).
Rage is hard to define. Blind rage is easier to describe. But cold rage is a thing too. One man (later imprisoned for serial rape) told me certain people evoked cold rage in him; a deep desire to harm them. A certain type of person. His victims were within that group. The cold rage was daily, he felt it followed him around like a cloud, sometimes enveloping him. He was rather hyper-vigilant (paranoid) too. No known mental illness. His identical twin was already in prison for violent crimes when I did that interiew.
And so now I ask anyone who will tolerate my technique to talk to me about rage.
I really do not think I've ever experienced it. I've been angry, but when I'm angry, I consciously decide what to do and say. No examples of amnesia or blind rage that I know of. When I used to drink in college, I'd forget some of the night before - but I wasn't in a rage, I was being ridiculous instead.
I usually react by putting up walls and barriers to the presence of the angry-making person or situation, or I may write a letter or I might make one of my sharply focused speeches. On a daily basis, I feel extreme sadness about the cases we discuss, and the ones that make me feel what I think might be rage are Gannon's case and Suzanne Morphew's case. I am so angry - but I experience no blank states of mind, no impulsivity, no need to plan to go mess with Barry Morphew etc. So I don't understand it any better than anyone else does. Despite years of trying. I don't suddenly lash out at anyone and I've lived with some very difficult people.
There's a book (Rage of a Headhunter) that has helped me very much, though. It appears that rage may be an accumulation of un-discharged anger. Oddly, in that study, when people were very very angry, their anger subsided each time they told someone else about the person who made them so angry (it was always over a person).
Seeing a loved one harmed was the most common trigger, in that study. That may be relevant in this case, as well.