My longest depression was before any sort of treatment and it was maybe a year and a half. Since starting treatment they're up to a month or two though I do have depressive "blips" that are just a couple hours or a couple days that I wouldn't call episodes. I'm sorry you've been having such a rough go of it lately; I hope the depression lifts soon. How long have you been on the wellbutrin? It might take some time to get to a point it's fully working.