Lots of depression in my immediate family (100%) and anxiety-based disorders on my dad's side. When I asked dad about family mental health history, he said that he thought my mom was bipolar.

I thought that was complete BS at first, because I had heard (and been told by T) that if your parent was bipolar you would know it. Then heard my grandma and aunt talking about things that were totally contrary to what I remember. And recently it occurred to me that if mom was BP II, that might actually explain a lot, and could be something a kid would be oblivious to (especially ADD kids, as we all were...)

Not that it's possible or advisable to make posthumous dx's, but... She would get into rages over small stuff on occasion and was sometimes very irritable - the walk on eggshells sort of thing. I remember her being very high energy, outgoing, and joyful at times, but especially later in life (late 40's and early 50's, she died at 53) she was depressed a lot to the point of being suicidal (god, those were awful phone calls to get), totally isolated, and had major, major scary sleep problems, so if there was some kindling effect or very slow cycling, I could see that being something that had been unnoticeable earlier but came out in force later when she lived alone. Now that I think of it, she also said stuff from time to time that could easily suggest psychotic symptoms, but hard to evaluate for someone outside the specific situations (everyone at work was against her, etc.)

My memory is fuzzy enough that it's hard to speculate and I don't really know. Even if my mom did pass on BP to me, she gave me so much more that I would never hold it against her for a second.