How does a doctor determin if you are bipolar depression?

A: Group of symptoms, good history and exclusion of any other medical causes, good luck.

Mania: Depression in the context of bipolar disorder is associated with a history of manis.

History: This is a diagnosis determined by patient history.. Bipolar usually involved two or more swings between 'mania' and 'depression', measured over a lifetime. This is best determined by a specialist - a counselor or psychiatrist.