The four basic types of bipolar disorder are: Bipolar I disorder Bipolar II disorder Cyclothymic disorder Unspecified bipolar and related disorders All four types involve changes in mood, energy, and activity levels that impede daily functioning, interrupt healthy relationship development, and can jeopardize personal safety. Bipolar I Disorder: To be diagnosed with bipolar I disorder, a person must have a manic episode that lasts at least seven days or have manic symptoms so severe that immediate hospitalization is required. Usually, an individual who meets this criteria has also experienced one or more depressive episodes, but that is not necessary for diagnosis. Between periods of mania and depression, individuals with bipolar I disorder can feel normal. Bipolar II Disorder: Individuals with bipolar II (vs. bipolar I) disorder do not enter states of full-blown mania. Instead, they experience depressive episodes — sometimes longer and more severe than those experienced by individuals with bipolar I disorder — interspersed with hypomanic episodes. Between periods of depression and hypomania, individuals with this condition can feel normal. Cyclothymic Disorder: Cyclothymic disorder is a milder form of bipolar disorder. Individuals with this condition experience a chronically unstable mood with alternating hypomania and depression symptoms for at least two years. Though these symptoms are less severe than the symptoms associated with bipolar I or bipolar II disorder, they impede day-to-day functioning. Other Specified/ Unspecified: Those who do not meet the diagnosis criteria for bipolar I, bipolar II, or cyclothymic disorder but still experience significant mood swings and/or mood elevation may receive a diagnosis of “other specified” or “unspecified” bipolar disorder.