Which of the following is a feature of cyclothymic disorder?

Cyclothymic disorder is characterized by a pattern of chronic fluctuating mood disturbances involving periods of hypomanic symptoms and periods of depressive symptoms that last for at least two years in adults (or one year in children and adolescents). These mood fluctuations are less severe than those seen in full-blown bipolar disorder. The presence of these alternating hypomanic and depressive symptoms, which do not meet the criteria for a major depressive episode, is what distinctly defines cyclothymic disorder.

While consistent low mood and severe manic episodes are associated with other mood disorders, cyclothymic disorder specifically involves these milder, yet chronic, fluctuations instead. The disorder does not present with only depressive symptoms, as that would align more closely with major depressive disorder rather than cyclothymia. Therefore, the key feature highlighting the nature of cyclothymic disorder is the presence of both hypomanic and depressive symptoms over time.