First, a perspective on depression. Being sad is like having someone throw some black pepper in your nose, where a person may sneeze once, twice or a dozen times. But once the sneezing is over, it’s over because it came from an outside source.
Depression is akin to pneumonia, as in, it is a severe constant that has an internal causality. Having other negative things happen to one’s physical fitness when one has pneumonia can make it worse and cause death.
Speaking of the negative. Depression is the world of the negative. If you approach someone that is in that state, with negative based motivations, you’re just acting as an exponent to that formula.
IE. The fear based “eternal damnation” approach. Read up on how effective that is for the kids that go through the “Gay Conversion Therapy” process. RE. Their suicide rates are extremely high because they’ve had negatives upon negatives piled upon them.
The guilt based approach isn’t any better. RE. “Think of your friends and family.” This is forcing the person to attribute another negative to themselves.
There is a difference however, between someone who doesn’t want to exist anymore and someone that doesn’t believe that they should exist anymore. The difference being the perceived self assessment vs. other’s assessment of one’s self. There are also blends of those conditions.
If you’re serious about wanting to know more about what motivates people to kill themselves, then I suggest that you search for autobiographies written by people who have attempted to commit suicide. There are a lot of them out there and they put a lot of work into exposing their souls for people to learn from.