Cyclothymic Disorder By William Coryell, MD, University of Iowa Carver College of Medicine Reviewed / Revised Aug 2021 | Modified Sep 2022 View Patient Education Treatment Cyclothymic disorder is characterized by hypomanic and mini-depressive periods that last a few days, follow an irregular course, and are less severe than those in bipolar disorder; these symptom periods must occur for more than half the days during a period of ≥ 2 years.