You sound depressed yourself, OP, and are accusing everyone else who has ever suffered from depression of the same conduct as your friend.
OP, I've been where you are, and I am pretty sure I'm bang on about this.
Welcome to the board, Ayjey. I hope you stick around. Even though the OP deleted her post, there is no reason we can't carry on a discussion here about depression. I hope you don't feel guilty about your friend committing suicide. Usually it is not just one thing that causes someone to end their lives. It is a lot of things combined. It is years of emotional "erosion" that could lead someone to such an act. I have never known anyone personally who did themselves in. My sister is a psychologist and we talk about these things a lot.