According to identical twin studies, etc. Bipolar disorder isn’t strictly genetic. There are theories that latent genes can be switched on due to environmental reasons. Also if it’s a recessive gene that’s implicated, then yes, it can skip a generation.
But in my family, numerous people in every generation since at least my mother’s father’s mother has had bipolar disorder. Family functions can be…um…fun.
Actually in m y Family it did seem to skip a generation. My Grandfather was bipolar, but all 9 of his children (my dad) did not develop the disease. Although I do have 25 first cousins and 3 of us are bi-polar. I believe there is a susceptibility when it is in your family whether it is from your parents or grandparents.
Apparently not for my family at least; my father's side all have mental illness in the spectrum from bipolar disorder to schizophrenia (schizoaffective disorder included, but most of them have bipolar disorder including my father who was a rapid cycler) and I'm being told by someone going to school for this stuff who is "intimately familiar" with each diagnosis (according to them) that my relatives starting with my grandmother on my mother's side sound like they have schizophrenia. But I've also been told my mother sounds like she has borderline personality disorder so I'll probably never know for sure because trying to convince the family members potentially with schizophrenia to go get an evaluation is like banging your head against a brick wall. Somehow myself, I ended up with schizophrenia and apparently not enough mood issues to be able to be diagnosed with a mood disorder as well (to end up with schizoaffective disorder) even though the bipolar disorder runs stronger in the family.
No but like any other disability or condition that is genetic it can express itself in some people and not in others. The bipolar spectrum from cyclothymia (mild bipolar) to schizoaffective disorder (which I have) runs throughout my family so how it expresses itself varies as well.