Is depression genetic?

According to a book by Kelly Brogan, MD, there is not one study that proves depression is a chemical imbalance. Own Your Self: The Surprising Path beyond Depression, Anxiety, and Fatigue to Reclaiming Your Authenticity, Vitality, and Freedom It has also never been proven that depression is genetic. 

11 depression causes:

1. Low vitamin D

2. Low vitamin B12

3. Low zinc/chromium 

4. Low blood sugar—high insulin 

5. Lack of sleep 

6. Fatigue 

7. Postpartum—low estrogen 

8. Menstrual cycle

9. Medication side effects 

10. Stress—loss

11. Environmental situation