Cyclothymia

Figure 1. Cyclothymia is characterized by fluctuations between depressive symptoms and symptoms of hypomania, but it is less severe than bipolar disorder.

Cyclothymic disorder is a mental disorder that involves numerous periods of symptoms of depression and periods of symptoms of hypomania. Symptoms, however, are not sufficient to be a major depressive episode or a hypomanic episode. Symptoms must last for more than one year in children and two years in adults.

Cyclothymia is classified in DSM-5 as a subtype of bipolar disorder. The criteria are listed below:^[1]

1. periods of elevated mood and depressive symptoms for at least half the time during the last two years for adults and one year for children and teenagers
2. periods of stable moods last only two months at most
3. symptoms create significant problems in one or more areas of life
4. symptoms do not meet the criteria for bipolar disorder, major depression, or another mental disorder
5. symptoms are not caused by substance use or a medical condition

People with cyclothymia experience both depressive phases and hypomanic phases (which are less severe than a full hypomanic episode). The depressive and manic symptoms in cyclothymia last for variable amounts of time due to the unstable and reactive nature of the disorder. The depressive phases are similar to major depressive disorder and are characterized by dulled thoughts and sensations and the lack of motivation for intellectual or social activities. Most people with cyclothymia are generally fatigued and tend to sleep frequently and for long periods of time. However, other people experience insomnia. Cyclothymia differs from bipolar in that major depression, mania, or hypomania have never occurred.

The cause of cyclothymia is unknown. Risk factors include a family history of bipolar disorder. First-degree relatives of people with cyclothymia have major depression disorder (MDD), Bipolar I disorder (BD I), and Bipolar II disorder (BD II) more often than the general population. Individuals may also have a history of higher risks for substance-related disorders within the family.  First-degree relatives of a BD I individuals may have a higher risk of cyclothymic disorder than the general population.

Treatment is generally with counseling and mood stabilizers such as lithium. It is estimated that 0.4%-1% of people have cyclothymia at some point in their life. Onset is typically in late childhood to early adulthood and males and females are affected equally often.