Both bipolar disorder type 1 and bipolar disorder type 2 are characterized by one or more major depressive episodes, but the type and degree of mania differ.

People with bipolar type 1 experience mania that consists of distinct periods of persistently elevated, expansive, or irritable mood. These episodes are severe enough to cause trouble at work and at home. The mania may involve delusional ideas and impaired judgment.

People with bipolar type 2 experience what's called hypomania, which is milder. They often have an elated mood, although they can become irritable or aggressive. Impaired judgment is rare. Symptoms can be so mild that patients—and their doctors—mistake these periods of good mood for recovery between depressive episodes.

Both types of bipolar disorder occur with the same frequency: the lifetime prevalence of each is around 1 percent. Although bipolar type 1 occurs equally in men and women, bipolar type 2 is more common in women.

If your depressive episodes come and go, talk with your doctor about your moods between episodes. If you feel unusually energetic or say or do things that are out of character, you may have bipolar type 2. While the hypomanic periods may not cause problems, the risk of them cycling into depression is high. To treat the depressive symptoms, you need to treat the hypomania. Getting the correct diagnosis is crucial.

Publication Review By: Karen L. Swartz, M.D.

Published: 17 Aug 2013

Last Modified: 02 Sep 2015