I was desperate (in a depressed, "this life isn't worth living" way) over the summer because of a health condition. I managed to fix it, but I wouldn't say it was optional in the sense that it was about a story I was telling myself that I could change at will. I wasn't able to just snap out of it with application of the proper workshop or talk therapy. In fact, that was precisely why I knew it was a health condition, because I can usually change my mood at least a little bit by changing my way of thinking and/or my habitual behavior.
I did learn something from that, though, which I can apply now that I'm out of the desperation part: when desperate (which means "without hope,") go ahead and be desperate, and simply move one slow step at a time in a direction that looks like it'll be different from where you are now. Why not - you're without hope, so you have nothing important to lose.