Causes of Bipolar Disorder

While there are many biological factors associated with mania and depression, the exact cause for bipolar disorder is unknown.

At least 50 percent of people with bipolar disorder have a parent with a mood disorder—most often major depressive disorder. A person has a 30 percent chance of inheriting a mood disorder if one parent has bipolar disorder, and a 60 percent chance if both parents have it. Research has found an even greater risk among twins, especially identical twins, who have a parent with bipolar disorder.

New mothers with bipolar disorder have an increased risk—30 to 50 percent—for an episode during the first month after childbirth. This means that the pregnancy must be managed properly to ensure safety for both mother and child.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 31 Jan 2001

Last Modified: 02 Sep 2015