Statement from Mayo Clinic issued Monday:
"Following extensive evaluation, Congressman Jesse Jackson, Jr. is undergoing treatment for Bipolar II depression at Mayo Clinic in Rochester, Minn. Congressman Jackson is responding well to the treatment and regaining his strength.
"Many Americans have bipolar disorder. Bipolar II disorder is a treatable condition that affects parts of the brain controlling emotion, thought and drive and is most likely caused by a complex set of genetic and environmental factors. Congressman Jackson underwent gastric bypass surgery in 2004. This type of surgery is increasingly common in the US and can change how the body absorbs food, liquids, vitamins, nutrients and medications.