Some 10 million Americans are suffering with bipolar disorder. Also known as manic-depression, the disease is characterized by intense periods of elevated mood, or mania, alternating with periods of depression. Sufferers may seem euphoric one minute and despondent the next. In addition, these cycles may seem unpredictable, with no apparent trigger or cause.

That said, not all people diagnosed with bipolar disorder exhibit the same behaviors or require the same medications. The Depression and Bipolar Support Alliance categorizes the condition into the following five categories. If you suspect that you or a loved one may be suffering from any type of bipolar disorder, it's important to consult with a health-care professional. He or she can give you an accurate diagnosis and make treatment recommendations.

Bipolar I Disorder:

This is the most severe form of the illness, characterized by one or more extreme manic episodes or mixed episodes and one or more major depressive episodes.

Bipolar II Disorder:

This disorder is diagnosed after one or more major depressive episodes and at least one episode of hypomania, with possible periods of level mood between episodes. Hypomanias are extreme highs as compared to manias in bipolar I. This disorder can be misdiagnosed as major depression when hypomanic episodes go unreported.

Not Otherwise Specified (NOS):

This type of bipolar disorder fails to follow any kind of specific pattern (for example, recurring hypomanic episodes without depressive symptoms). NOS may also be indicated when bipolar disorder is present but is not the patient's primary disorder.


This milder form of bipolar disorder is characterized by several hypomanic episodes and less severe episodes of depression that alternate for at least two years. The severity of this form can change over time.

Rapid Cycling:

This form of bipolar disorder is diagnosed when a person experiences four or more manic, hypomanic, or depressive episodes in any 12-month period. Rapid cycling can occur with any type of bipolar disorder and may be temporary for some people.