This comes from the work of Dr. Carl C. Pfeiffer Ph.D., M.D. I edited my post, indicating this is what my primary care MD told me. I apologize. Here is a link to a discussion, but this is not where I got my information:
http://neurotalk.psychcentral.com/thread30724.html
Also:
http://www.raysahelian.com/pyridoxal5phophatep5p.html
This explains it best...
I just came across this thread, which has been going a long time. I have the problem, too, and it's obviously hereditary, in both my parents and their relatives. Some of you have not gotten any relief from the gluten-free diet. I get the anger when glutened, but for me, there is something else that keeps it going longer, and causes the problem by itself....