Most of us here know, [ because of Rose's great info ] the terrific qualaties of B12, but it also good for depression as well.
I know of this because many years back, a family member was in a terrible state of depression, she was willing herself to die, because she was very close to her mother and sadly she died, and that just flatened her completely.
She was given regular B12 shots from the doctor and was told to eat one meal of lambs fry per week, because of the high amounts of b12 in it, it took a few months but the deppression lifted, and she was her old self again, thank god and B12 too