I think you're jumping to conclusions a bit, based on your own experiences. It's textbook bipolar behavior, sure, but it's also textbook a-hundred-other-things behavior as well.
Take me, for instance: as far as I know, I'm not bipolar, or anything else. The best framework for understanding myself I've found is that I'm an INFP.
Though it might look like I prefer to work in bursts and then chill out for a while, the reality is that few things stress me out more than deadlines, and getting into a flow can take a while; while I'm in it, I'm reluctant to let it go prematurely, so I end up going until I tire out, and then I need a rest, which (in a perfect world) can sometimes take two or three times as long as the preceding flow period. I'm also only really motivated internally -- doing things just because I'm supposed to is a recipe for me doing them badly, but doing things I care about is nearly always a recipe for producing very strong work.
I'm also pretty emotionally-driven (from the MBTI standpoint, I'm Fi-dominant) and am drawn towards my negative (Te-inferior), so it's no surprise that I do creative work (music) that requires lots of control and technical know-how (writing music to picture i.e. solving a problem, lots of gear to understand; this draw-towards-the-negative is why I've ended up frequenting a place like HN -- I like the control that programming gives me, even I'm still quite an amateur). This industry has terrible deadlines though, so that's still a problem that I simply endure, and do my best to work around with workflow and efficiency hacks.
Being primarily motivated by my feelings and values means that I can easily get into a slump. It's like depression, but as far as I can tell, probably not "real" depression. Just more like "Highly-Sensitive Person" living.
From the outside, I suppose that my way of being could totally be seen as bipolar or something like that. But the devil is in the details. All sorts of states can produce similar results.