I took a test at treatment back in 2006. one of the questions was, if I had ever had a cuncussion. At the time I wondered why this question would be on this test. Answering questions on AMHD has got me thinking about so much lately...
I was thinking, It might be head trama that inhibits the logic of "normal behavior."
Rockie

Asking again, still curious...

I'm not a big fan of wikipedia,as anyone can contribute to it without an ounce of credibility but they seem to have covered this topic rather well.
It will give you a starting point for further investigation,if nothing else.
Also,in any mental health treatment all brain injuries have to be documented to determine if the emotional problem could have a physical basis.

Post-concussion syndrome - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Post-concussion_syndrome)