Bipolar disorder, formerly known as manic depression, is a mood disorder that causes extreme fluctuations in mood. It is called bipolar disorder because mood states can alternate between the "poles" of depression (sad or empty mood) and mania (high, elevated or irritable mood). The fluctuation in moods vary in duration, some people experience changes in mood every few hours or days while others experience mood swings over a period of weeks or months. Another mood state that occurs with bipolar disorder is a mixed episode where symptoms of mania and depression are experienced simultaneously. This state tends to be the most frustrating and the most dangerous of the mood states. During mixed episodes, people have reported feeling as if they are being pulled in two different directions at the same time; they are more prone to substance abuse and suicide attempts. Get Tomorrow's Treatments Today if you qualify. Clinical Trials starting soon.