Yeah IDK what the big disagreement is here when it's been proven that TBI cause personality changes and all kinds of irrational logic tracks.
http://www.brainline.org/content/201...y_pageall.html
People can have completely new, volatile personalities, making it extremely difficult for their loved ones to cope.
There was a very good British documentary about it, wish I could find it. In that case, the father suffered a traumatic brain injury in an accident and cam back extremely short fused, would freak out all the time and act violently when he never had before, and occasionally he would realize who he was and freak out over what was happening to him, but his wife was leaving him and taking the kids.
http://www.tbiguide.com/angerdepress.html
So an already quick-tempered person with a traumatic injury would have even more of a trigger.