I think Steve and JWfacts nailed it. We don't really "all know that suicide rate among JW's is high". We suspect it might be compared to the general population of the individual countries they are active in. But we don't really know. It might be the same as the normal population (which is what I suspect), but because of the small community word travels fast.
Also, I don't believe they actively or subliminally encourage suicide. That would be folly when you are already hemorrhaging members to the tune of 60-80K a year.
But feeling like you are not good enough, that the entire world will be destroyed.......these things can't help.