Joni Eareckson Tada says that when she was a teenager, she prayed for God to help her know his presence and grace more. She says she knew she was a hypocrite. A month or two later, she had a diving accident that left her a quadraplegic, and even then she saw the accident as the answer to her prayer. She was angry at God at first, but then came to believe that God could not have gotten her attention any other way.
A friend also went through PPD and says that she is grateful for having it because it drew her closer to God. I can't say yet that I am grateful for having PPD, but it has taught me things I needed to learn: my own fallibility, how to receive help, and more compassion for others' suffering. If I had to have PPD to learn these things, then perhaps it is worth it. I am not sure I have drawn closer to God yet, but I think I will because through PPD God has shown me truth about myself: He is worshipped in spirit and truth, and so I can worship him more the less I live under illusions.