Their stress comes from reality, and especially others succeeding in it. They've given up on life and thrown their lot in with the rest of the hopeless. The worst thing for them is seeing the evidence in others that it's not all for nothing and that there is purpose to life, because their very identity relies on misery and hopelessness. So they have a pretty powerful cognitive dissonance when they are presented with belief in God or happy families and people helping each other of their own will.