U.S. Rep. Jesse Jackson Jr. (D-Chicago) is being treated for bipolar disorder, according to an announcement by the Mayo Clinic in Rochester, Minnesota. Jackson is "responding well to the treatment and regaining his strength", according to the statement. 

Here is more from the Mayo Clinic statement, according to the Chicago Tribune.

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 U.S. and can change how the body absorbs food, liquids, vitamins, nutrients and medications.

Congressman Jackson has asked Mayo Clinic to distribute this information on his behalf. He and his family remain grateful for support and prayers offered and received on his behalf.

U.S. Rep. Jackson has been on medical leave since June 10. There are still no details on when the congressman plans to return to work or resume campaigning for the election, as detailed by his wife, Ald. Sandi Jackson (7th), last week.