cy·clo·thy·mi·a 
(sī′klə-thīmē-ə)
(sī′klə-thīmē-ə)n.
A mood disorder characterized by alternating periods of elevated and depressed mood that are milder than those typical of bipolar disorder. Also called cyclothymic disorder.
cy′clo·thymic (-mĭk) adj. & n.