The major feature of cyclothymic disorder is a chronic, fluctuating mood disturbance including plentiful periods of hypomanic symptoms and periods of depressive symptoms (Criterion A).

During the initial 2-year period (1 year for children or adolescents), the symptoms must be persistent and any symptom-free intervals last no longer than 2 months (Criterion B).

The diagnosis of cyclothymic disorder is made only if the criteria for a major depressive, manic, or hypomanic episode have never been met (Criterion C).

The cyclothymic disorder diagnosis is not made if the pattern of mood swings is better explained by other specified and unspecified schizophrenia spectrum and other psychotic disorders (Criterion D).

The mood disturbance must also not be ascribed to the physiological effects of a substance or another medical condition (Criterion E).

Although some individuals may function particularly well during some of the periods of hypomania, over the prolonged course of the disorder, there must be clinically significant distress or impairment in some important areas of functioning as a result of the mood disturbance (Criterion F).