Bipolar disorder is a mental condition sometimes referred to as manic-depressive disorder because it is associated with mood swings that range from depression to mania. Depression is characterized by feeling sad or hopeless and mania usually consists of feelings of euphoria or increased energy. Mood shifts may occur only a few times a year, or as often as several times a day. Bipolar disorder is divided into several subtypes:
i. Bipolar I:
Mixed episodes or manic episodes that require hospitalization or last for a few weeks. Depressive episodes are also often problematic for patients; these typically last for a minimum of two weeks
ii. Bipolar II:
Defined by a pattern of depressive episodes and hypomanic episodes, but not the full-blown manic episodes that are seen in Bipolar I.
iii. Cyclothymic disorder (Cyclothymia):
defined by numerous periods of hypomanic symptoms as well as numerous periods of depressive symptoms lasting for at least 2 years. However, the symptoms do not meet the diagnostic requirements for a hypomanic episode and a depressive episode.
Bipolar Disorder. National Institute of Mental Health. https://www.nimh.nih.gov/health/topics/bipolar-disorder/index.shtml