Whenever I hear of people that are so depressed that they become suicidal, I ask them to think about it. They may have a troubled past, no family, addictions, etc...but there is always one person out there who cares. I make them think about that one person, and how they would be letting them down. They may mean the world to that person (isn't there a quote like that?)

I also tell them that you can't take suicide back. You can't say "wait, no, I didn't really mean to die! I take it back!" because you can't take it back