The types of bipolar disorder are categorized by the length, frequency, and pattern of episodes of mania and depression.
Bipolar I Disorder
Bipolar I disorder is characterized by one or more major manic episode and one or more major depressive episode. Bipolar I disorder is the most severe form of the illness.
Bipolar II Disorder
Bipolar II disorder is characterized by one or more major depressive episodes and at least one episode of hypomania — similar to bipolar I highs but not as severe — with possible periods of level mood between episodes.
Not Otherwise Specified
Bipolar disorder that does not follow a particular pattern is called bipolar disorder not otherwise specified.
Cyclothymia
Cyclothymia is a milder form of bipolar disorder characterized by several hypomanic episodes and less severe episodes of depression that alternate for at least two years.
Rapid Cycling
Rapid cycling is characterized by four or more manic, hypomanic or depressive episodes in any 12-month period.
