I'm the first and only person in my family to be diagnosed with bipolar, although looking back, I'd be willing to bet that my mother had it too. She was very mercurial and moody, but of course mental illness did not exist in our family.....and if you didn't believe it, all you had to do was ask her.

There is a lot of depression and anxiety in my family, including a grandmother who once spent some time in a "sanitorium" for a "nervous breakdown" and a sister with dysthymia. And I have a son who leaves little doubt that he is an undiagnosed BP, as he's had wild mood swings his whole life. We took him to therapy appointments from the time he was in preschool, but no one ever thought to refer him to a pdoc. I don't know how he passed the psych eval going into the Army back in '08, but he did. He wound up with PTSD after his tour of duty in Iraq and one Army psychologist wanted to dx him with BP as well, but didn't because he wanted to continue his military career at the time. (He is now out.)

Honestly, one doesn't have to have ANY bipolar in their family to be diagnosed with the illness. It makes a stronger case in people who aren't clearly BP, but is not required to make the dx.