It was explained to me by a psychologist that research has found that in order to find the genetic link for bipolar disorder you may have to go back as many as 7 generations. And who on earth knows much about their family beyond a couple of generations?

Until our generation, people just did not get help for mental health issues, so much has to be speculation.

I have no solid genealogical evidence for mental illness. The closest I can come is that my grandmother definitely had her quirks, but the family stories about her are mostly found funny (which says a great deal about my family's enlightenment).

Eloise, your family may be right when they say your great-grandfather's problems were an issue of aging. That is a distinct possibility. They may have more solid memories of him prior to his problems than you do. That's one of the difficulties with this.