I don't think many "civilians" understand depression--but they aren't freaked out by it and over-the-top-judgmental of those suffering from it. An even tinier fraction (including most medical doctors) know anything about bipolar disorder--even the difference between bipolar I and II.
TV, films, journalism ... none do bipolar folks any favors. We're the last east favorite preformed type for villain. Thanks to some real life bad guys who were bipolar and other stuff, including poor samples of humanity, the bipolar label alone is enough to freak most people totally out.
I'm a bipolar II alcoholic, and in lots of circumstances I'll acknowledge being an alcoholic. I wouldn't tell anyone I'm bipolar, except my T and pdoc though. Because the minute I do, I have too much to overcome in the minds of most people. I've taken the chance, with a couple of people very close to me--and they never got past their (wrong) preconceptions, in spite of having known me for decades.
If I were in a relationship, I'd have to re-evaluate--but I don't thing I'd decide differently unless my partner already had knowledge of & personal experience with bipolar folks before meeting me.
Roadie