Doctors at the Mayo Clinic in Rochester, Minn., have confirmed that U.S. Rep. Jesse Jackson Jr. is being treated for bipolar II depression.

In a statement, they say he's responding well to treatment and regaining strength.

The statement added:

“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.”

This announcement comes more than two months after Jackson started a leave of absence.

Intially, aides said he was being treated for exhaustion.

According to the Mayo Clinic website, bipolar disorder -- sometimes called manic-depressive disorder -- is associated with mood swings that range from the lows of depression to the highs of mania.

The Mayo Clinic's statement said bipolar disorder can be controlled with medications and counseling.