Candida can definately cause emotional issues. I was on Effexor for Depression for 10 years before going on Difulcan for seven days last November. About a week after taking it, I stopped taking the Effexor, not because I intentionally did so, but because I would keep forgetting to take it. One day, about six weeks later, I realized that I had not taken Effexor for weeks and felt wonderful. I was delighted.
I've read that the emotional issues are caused by the toxins that candida gives out, including an alcohol, which is a known depressant. Here is an article on how candida can cause emotional problems: