Cyclothymia, also called cyclothymic disorder, is a mood disorder related to bipolar disorder. In the same way that dysthymia is a long-lasting but less intense version of major depression, cyclothymia is a less intense version of bipolar disorder. The highs and lows of cyclothymia are less extreme than the highs and lows of bipolar disorder, although they cause more trouble than the usual ups and downs of life.

This mood pattern can begin early in life (in the teens or 20s) and last indefinitely. It is equally common in both sexes, and it runs in families, which suggests that there is a genetic component.

In cyclothymia, symptoms of either hypomania or depression are present most of the time for at least two years.

Symptoms of hypomania include the following:

Symptoms of depression include the following:

If symptoms of hypomania or depression become severe enough, the diagnosis may be changed to bipolar disorder or major depression. (As many as 25 percent to 50 percent of those with cyclothymia are later diagnosed with bipolar disorder).

If untreated, cyclothymia can lead to disturbed personal relationships, difficulties at work, and alcohol or drug abuse. Often these problems are regarded as the person's normal way of life. As a result, the underlying mood disorder is not detected.

Once a diagnosis is established, treatment can reduce the duration and intensity of symptoms. It can also reduce the risk of developing bipolar disorder or major depression.