Tell me if depression form into bipolar disorder?

Either a person has: A predisposition for bipolar disorder or they don't. However, a person may initially have one or more episodes of clinical depression & then at a later time have either a hypomanic or a manic episode (s). These are periods of ^ energy, ^ impulsivity, ^ productivity with agitated, irritable or euphoric mood. At that point it would become apparent that the person has some form of bipolar disorder.