Bipolar II disorder (pronounced "bipolar two") is a form of mental illness. Bipolar II is similar to bipolar I disorder, with moods cycling between high and low over time.
However, in bipolar II disorder, the "up" moods never reach full-blown mania. The less-intense elevated moods in bipolar II disorder are called hypomanic episodes, or hypomania.
A person affected by bipolar II disorder has had at least one hypomanic episode in his or her life. Most people with bipolar II disorder suffer more often from episodes of depression. This is where the term "manic depression" comes from.
In between episodes of hypomania and depression, many people with bipolar II disorder typically live normal lives.
Who Is at Risk for Bipolar II Disorder?
Virtually anyone can develop bipolar II disorder. About 2.5% of the U.S. population suffers from some form of bipolar disorder - nearly 6 million people.