There's situational depression (my mom died, my girlfriend dumped me, etc.) and then there's depression. Winston Churchill called his The Black Dog. It is relentless and not related to any situation you are in. If you don't understand then be thankful.

The cause is not entirely clear. SSRIs do not help you "bury it." It's not an emotional problem or a lifestyle problem or anything like that. There's no "it" to bury. SSRIs seem to remove whatever cause is in your brain/nervous system. They literally are lifesaving drugs with almost no side effects for many people!