My depression hit when I was 50 but it is the 'secondary' type of depression that is caused from circumstances and not the chemical imbalance type. I found myself coping with my disability along with the death of my husband and a few other challenges thrown into the mix and it was more than I could handle and that is when the depression came along. So I think it depends on what a person's circumstances are along with their biological make-up and history. (()) to everyone - Patricia