depression is strictly psychological so you should focus on that if you want to really fix it.
there is no diet of any kind that cures depression. some foods may provide some help but it does not fix the root cause.
depression is cured by changing habits, environment, and working towards achieving something.
one of my friends was severely depressed and stressed, being in late 30s, single, no education, no job, feeling miserable, no goals in life, complete apathy. on top of that he had chronic GI issues like diarrhea and stomach pains.
so then he met a girl, moved in together, got married, went back to school, trying to start a family. the result - depression and stress all gone, all health issues are gone.