Bipolar disorder is a psychiatric disorder that causes people to alternate between episodes of depression and episodes of high energy or irritability (mania). In many people, episodes of either depression or mania are followed by periods of normal functioning.

Bipolar disorder is also called manic-depressive illness.

The cause of bipolar disorder is not completely understood, but it may be the result of a chemical imbalance in the brain. It is not known what causes this chemical imbalance. The disorder may run in families.

Bipolar disorder occurs equally among males and females. It often begins between the ages of 15 and 24.

There is no cure for bipolar disorder, but medicines and counseling may help control the symptoms. Seizure medicines and lithium are often used to treat bipolar disorder.