Sort to butt in again - but if we're living in daily, hourly expectation of the coming of the Lord Jesus to take us to be with Himself (at His coming), then wouldn't that sustain us? Really, we ought to be in constant expectation. I find that extremely testing, but I believe it's true. Even someone who is suffering a great deal can be sustained by that hope, that the Lord is soon going to come. If I choose to end my life because of suffering, I'm clearly not in the good of the truth of the imminent coming of the Lord.