It is impossible to fully appreciate how chronic pain changes one's life until you've experienced it first hand.
I have. And even though I never considered suicide myself, I understand why someone might. It's frickin' depressing to suffer unrelenting pain and face the possibility that this is now your life, forever. Opiates are a terrible solution, but I gobbled them like M&Ms out of desperation because there was nothing else.
I have to imagine that's true for psychological pain, too.