I have struggled since I was about 11. I always knew I was depressed because I felt hopeless and sad. Loss would just intensify it. I had a decent childhood but there were problems. My mom had a drinking problem and my dad had either depression or bi-polar. Will never know for sure. Some of us have good and bad in our lives and some of us suffer extreme trauma and abuse. I haven't be traumitized or abused and I can be deeply depressed.

I like to think it is a chemical imbalance because that is somewhat treatable.