What is bipolar disorder?
Bipolar disorder is a cycling mood disorder characterized by alternating periods of depression and mania. A mood disorder is a mental illness characterized primarily by mood swings or an abnormally high or low mood. Manic episodes are periods of abnormal highs in mood. Depressive episodes are periods of abnormal lows in mood. Bipolar depression may also be called manic depression.

How common is bipolar disorder?
According to the National Alliance on Mental Illness, about 2.3 million adult Americans, or around 1.2 percent of the population, are diagnosed with bipolar disorder. The condition occurs across all races and ethnic backgrounds. In general, men and women are affected equally. However, men are more likely to experience a manic episode before a depressive episode. Women, on the other hand, are more likely to have a major depressive episode before a manic episode and are more likely to have more depressive episodes than manic episodes. Women are also more likely to experience rapid cycling. Rapid cycling occurs when a woman has four or more episodes per year.

At what age is bipolar disorder most likely to develop?
The onset of bipolar disorder usually occurs in late adolescence or early adulthood, and the average age at onset is 20. However, the disorder can occur at any age, including over 50. Bipolar disorder was once thought to be very rare in children under the age of 12, but recent studies show it may be more common than was previously believed.