I don't really know whether my family members were formally diagnosed. All I know is that there is MI generally in my background based on their behaviors. My maternal grandma was in and out of the psych hospital back in the 60s and 70s and eventually died from alcoholism. My dad was often very paranoid, anxious, and depressed, and he died from alcoholism too. My maternal uncle died from alcoholism. My mom has been on Xanax for anxiety. So I don't know a lot of the details, but it's clear to me that there are issues. My mom describes my grandma as having been happy and affectionate at times and brutally abusive at others. My dad alternated between high success in his career and total isolation. Bipolar makes sense based on what I know of them, but you're right that I don't know for sure whether there was a formal diagnosis.