What are the most common causes of bipolar disorder?

What are the most common causes of bipolar disorder?

Christopher Reist (Academic Psychiatrist, Co-Author of “Psychiatry”) gives expert video advice on: What's the difference between "major depression" and "bipolar disorder"?; Is there anything I can do to avoid developing bipolar disorder? and more...

We really don't understand what the causes of bipolar disorder are. Certainly there is evidence for a genetic predisposition but, beyond that, it's very difficult to predict who might develop bipolar disorder.