Depression is brought on by lifestyle, diet, etc a lot more than anything. There are some countries in the world where depression literally doesnt exist, ive seen it. The reason america has so much "depression" is because of the stress of life, general lack of religion (Im not really religious, but this definitely has something to do with it), poor economy etc. I guarantee you a lot of these people who claim to be depressed could get over it if they focus on the cause of it. I used to be "depressed" when I was younger and I got over it, and I know nearly everyone else can too.
Especially when someone has a family, wife etc, many things other people would kill to have so they can be happy, then they go kill themselves, I have a hard time feeling remorse for these people. Im sorry. Suicide is an extremely selfish act.