Causes
The exact causes of cyclothymia are not known, but it is often a result of the same genetic factors that cause bipolar disorder. In fact, there is an estimated 15% to 50% risk that people with cyclothymia will eventually be diagnosed with bipolar disorder following a full-blown manic episode or major depression.
People with cyclothymic disorder usually have a family history of major depression, bipolar disorder, suicide, or alcohol or drug dependence.