Cyclothymia is a chronic mood disorder
An individual with cyclothymia may feel stable at their baseline level but experience noticeable shifts to an emotional high during hypomanic episodes with symptoms similar to those of mania but less severe, and emotional lows involving depressive symptoms that do not meet the criteria for a major depressive episode.
To meet the diagnostic criteria for cyclothymia a person must experience this alternating pattern of emotional highs and lows for a period of at least two years with no more than two consecutive symptom free months. For children and adolescents the duration must be at least one year.
Specific criteria defined by the DSM-IV for a bipolar II diagnosis is as follows:
The presence of a hypomanic or major depressive episode.
If currently in major depressive episode, history of a hypomanic episode. If currently in a hypomanic episode, history of a major depressive episode. No history of a manic episode.
Significant stress or impairment in social, occupational, or other important areas of functioning.