Dreamer, bi-polar is an older more generic name for it, I did a paper for a 100 level physiology class in school (in essence a freshman college level social studies elective not much more advanced than a high school class) and we had group project, the group I was in we did our own reports and I chose manic depression (since others wanted to do different forms of depression and I had heard of this and didn't really know anything about it) it is different from other depression forms that it can have a reverse effect on the person tho it may rarely happen that they go super happy and have a super high. like the joy a person can get from graduating from school when they never thought they could do it, getting married, having been told they were going to have a baby, you know a cloud nine on top of the mountain sort of the deal, but most of the time they are normal at best or they make Eor (how ever you spell winnie the poo's donkey friend) look happy.... the other end of it is the person is over happy and it causes almost as many problems because they are too happy (and usually are how can I say it politely, they like being happy with someone in a personal manner) and they also would give some symptoms similar to ocd they go on buying sprees like a hoarder hordes and that's the manic state and then there is some who swing like a yo=yo back and forth, this is more rare...
I'm not a doctor, nor do I play one on TV but from memory they need adjustments in meds occasionally to keep an even keel so to speak, therapy helps some to at least keep some of the worst of it at bay, and lithium salts helps some but doctors don't perscibe it much (one source I remember reading said it had the same effects on the body as table salt (blood pressure, water retention issues) and the author could not find why since it seemed to be a silver bullet that seemed to cure or at least seemed to help a lot why the doctors couldn't prescibe blood pressure meds and water pills to counter the side effects...(.