Yep make sure you don't only eat but that you eat well.
Recently a health care provider found out that I had Candida - which is a form of gut fungi and cause leaky gut syndrome - strongly linked to mental illness, like depression, rage, anxiety and psychosis - all things I suffer from.
http://www.mindbodygreen.com/0-14177/anxious-moody-depressed-why-you-might-have-candida.html
She told me to stop eating sugar, yeast, sweet fruit and nuts to stop feeding the Candida. Four months later I have much more energy and go in me, I only get about 15 or 20 percent of the psychotic activity I had before and found an enormous lift in my mood mean it came to my depressive spells. I still cycle through my moods so my bi-polar hasn't completely healed but I have enjoyed a massive improvement especially in my psychotic part of my illness. The Candida has been reduced to normal levels and my gut should be healed or healing itself.
As you can see food is very important as well as supplements in some cases. For example I take high quality B complex tablets as well as Iron, Zinc, Magnesium and Vitamin C and take them every day this is partly responsible for having so much more (good) energy.
I have a friend who schizophrenic and he believed that only milk was true food. So for years that is all he consumed, after awhile I convinced him to use some cream as well (to stay warm in winter time) he was completely of the planet during this time and impossible to have a conversation with. He got into trouble and was put on an state order - so they force medications into him - and got him to eat properly again - I have my friend back again. Sure he is still a psychotic person, but at least we can spend time with each other again without going mad having to put up with him. Not only medicine abut also good food brought him back to some reason and he is doing really good now.