I don't know, but it seems to me that when one thing has someone feeling down, they tend to become irrational in the sense that their view on every other aspect of their life becomes distorted and viewed in a more negative way than, say, five minutes before hand.
You get a lot of people throwing this "It always gets better" bullshit around. It seems people in a depressive state seem to be on the opposite side of the spectrum, being positive that it never gets better.
In either case, you really don't know what the future has in store. And although I can't say from experience, it seems being able to recognize these negative irrational thoughts and take them for what they are may help one get through a suicidal state.
I would assume this would be easier said than done, maybe it's not even possible, I don't know.
Just maybe let that mole around the ol' noggin the next time you feel like taking the plunge?
That's my two sense. May be a life saver, may be a waste of typing. Let's hope for the former