I belive Depression is a symptom and not the original disease.
Bad nutrition, yeast problems, etc can produce depression.
I have been depressed for long time and I have been able to improve by just taking high doses of vitamin B, potassium and calcium/magnesium/zinc.
The vitmain B is clearly heping with my anxiety attacks.
If you do not want to try vitamins you can try superfood from Dr Schulze. Also bowel cleanes is important.
Mild exercise is needed.
Maybe 5HTP can also be helpful for you.
Good oils like olive oil are also needed for proper brain functioning.