Key statistics about bipolar disorder:

·         Bipolar disorder affects approximately 5.7 million adult Americans, or about 2.6 percent of the U.S. population age 18 and older every year. 

·         The average age of onset for bipolar disorder is 25 years old, although the illness can start in early childhood or as late as the 40's and 50's.

·         Bipolar disorder is the sixth leading cause of disability in the world.

·         Bipolar disorder is equally common in women and men.

·         Bipolar disorder is more likely to affect the children of parents who have the disorder. When one parent has bipolar disorder, the risk to each child is 15 to 30 percent. When both parents have bipolar disorder, the risk increases to 50 to 75 percent.

There are four types of bipolar disorder:

1.    Bipolar I disorder

 Bipolar I disorder involves periods of severe mood episodes from mania to depression.

2.    Bipolar II disorder

Bipolar II disorder is a more mild than Bipolar I disorder in regards to mood elevation. It involves a milder episodes of hypomania which alternate with episodes of severe depression.

3.    Cyclothymic disorder

Cyclothymic disorder involves periods of hypomania with short periods of depression that are not as long-term or pervasive as full depressive episodes.

4.    "Mixed features"

"Mixed features" is when a person experiences concurrent symptoms of adverse moods during manic, hypomanic or depressive episodes. Symptoms include high energy, sleeplessness, and racing thoughts. In conjunction with these symptoms, a person may also feel hopeless, despairing, irritable, and suicidal.

5.    Rapid-cycling bipolar disorder

Rapid-cycling is when a person has four or more mood episodes within a 12-month period. The episodes must last for a certain number of days in order to be considered an actual episode. Some people experience mood oppositions within a single day, or a single week. However, the mood transition may not be entirely noticeable to be considered separate episodes. While rapid cycling can occur at any time, some believe that it may be more common later on in the course of the illness. It seems that women are more likely to have rapid cycling than men. Rapid-cycling increases the risk for severe depression and suicide. Some say antidepressants may trigger or extend the length of rapid cycling.