I know for H (who I think has situational depression), once things with finances & his work resolve, the depression will go and not return until another sticky life situation arises. He has confidence he will not always be stuck with this depression. I am sure he will experience depression again, life is that way, loved ones pass away, bad things sometimes happen. I've really only known one other situation when H was this depressed. That was shortly after our daughter was born and he hadn't gotten the back surgery I'd urged him to have done when I was pregnant, he was in so much pain, he was crying and saying he wished he were dead. He got the back surgery and from recovery on, he was back to himself again. Depression completely gone. Whereas if it had been me with BP depression, surgery would have helped the pain, maybe briefly the depression, but it would have come right back if I was still riding out a depressive phase; if it was situational, then, my mood would have improved.

But I think it's possible for situational and BP depression to tangle and intermix. Really, the cause doesn't matter, you still feel like crap. And if it's BP but you have a situation going on, the stress from that definitely makes the BP worse.