The cause of cyclothymic disorder is unknown. Although the changes in mood are irregular and abrupt, the severity of the mood swings is far less extreme than that seen with bipolar disorder (manic depressive illness). Unlike in bipolar disorder, periods of hypomania do not progress into actual mania, in which the person may lose control over his or her behavior and go on spending binges, engage in highly risky sexual or drug-taking behavior and become detached from reality.

Hypomanic periods are energizing and a source of productivity for some people, while these periods cause others to become impulsive and unconcerned about the feelings of others, which can damage relationships. Because hypomania feels good, people with cyclothymia may not want to treat it.

• Alternating episodes of hypomania and mild depression lasting for at least 2 years
• Persistent symptoms (less than 2 consecutive symptom-free months)

The person's own description of the behavior usually leads to diagnosis of the disorder.

Cyclothymia is treated similarly to bipolar disorder. A combination of antimanic drugs, antidepressants, or psychotherapy can effectively treat this condition in many cases.

The stress of illness may be eased by joining a support group whose members share common experiences and problems.

People may decline to seek treatment during their cheerful and uninhibited moods. There is likely to be a need for long-term treatment.

There is a potential for eventual progression to bipolar disorder.

Call a mental health professional if you or your child experiences persistent alternating periods of depression and excitement that negatively affect work or social life.