I am bi-polar. I would say that mood swings (particularly severe ones) can cause a person to behave pretty out-of-character. I have definitely had times when I felt that life was not worth living. I have lived in extreme poverty under ridiculously dangerous and destitute conditions. But right now I am very stable at work, at home, and in my personal relationships. I have never felt homicidal or suicidal. I would argue to say that suicide could definitely be brought on by clinically significant, untreated mood swings. As far as homicide, if you are asking this question about someone that you know, I'd say use your judgement. Sociopathy, psychopathy, and schizophrenia are more likely to cause homicidal tendencies than bi-polar.
As far as the custody question, if someone is relatively stable, it shouldn't matter one bit if they have a diagnosis. I know many parents who have not been diagnosed with mental illness who are far less fit to raise children than most manic depressives that I know. Custody should be based (in my opinion) on the stability of the parent (financial & emotional) and the feelings of the children involved. I am also a child of divorced parents. Not that it makes me the ultimate authority, but I do have some first hand experience.
As far as the custody question, if someone is relatively stable, it shouldn't matter one bit if they have a diagnosis. I know many parents who have not been diagnosed with mental illness who are far less fit to raise children than most manic depressives that I know. Custody should be based (in my opinion) on the stability of the parent (financial & emotional) and the feelings of the children involved. I am also a child of divorced parents. Not that it makes me the ultimate authority, but I do have some first hand experience.