Bipolar is often inherited. A common trigger is a relationship which creates insecurity.
it doesn't
Some people with bipolar find that their moods vary with the seasons, having depressive episodes in winter and manic episodes in summer. Also, stress can affect it.
No.
Bipolar does run in families, though it doesn't affect everyone.
No
Yes, but diagnosis is much more difficult the younger the person is. It can easily be confused with many other things.
Bipolar disorder is not a disorder that comes in stages. If you are referring to how "bipolar" this person is, well, they are bipolar. So really, how moody they are depends on the day.
can it? yes, dramatically.
It doesn't. Get lost!
no known effect
No not really. You can tell a bipolar person from another. Bipolar persons will go through many mood swings. The person can feel happy about something one instant and then the next they could be sad or depressed. I would know as my mother is bipolar.
No it isn't. A person can not transfer being bipolar to you and it's nothing you can catch.