The term bipolar means "two poles," like the Arctic and Antarctica, and that image describes this disease pretty well. People with bipolar experience periods of depression interspersed with periods of mania, when their thoughts race and they behave impulsively and often irrationally.
Kathleen Brannon, 49, of Herndon, Va., had spent time in a state mental hospital for depression but was reluctant to agree that she was bipolar. "I'd have some periods of intense creativity where I would write for 20 hours," she says. "I hadn't thought of it as mania, I just thought I was driven to write."