This site deals with issues of depression and diet. I've only been reading there a short time so I don't know if any of the information would help with your spouse's clinical diagnosis but it may offer something in a way of an approach. Looking at some of the older posts you'll find her primer on dopamine/serotonin and other neurotransmitters.
I remember Nora's book having some information on depression/mental heath issues as well. I sort of stopped reading at that point but there may be some help there, too.
Good luck with your quest.
Retirement has afforded me the ultimate affluence, that of free time (Sahlins/Wells)