In the 13 years I spent in EMS I saw some horrid tragic suicide scenes. It was extremely sobering for me and served as a powerful motivation to get control of my automatic negative thoughts and feeling worthless. I have not beat it yet but I can keep it in the corner most of the time.
Aside from medication and counseling some of the best therapy is just talking with others who are managing it successfully. Those who have never had clinical depression have no idea what it is like and rarely take it seriously until they see someones brains painted all over a wall. That is the harsh reality if it is not addressed and is a terminal disease if left untreated.