Rep. Jesse Jackson Jr., D-Ill., whose mysterious monthlong leave of absence has perplexed Chicago and Capitol Hill, is at a residential treatment facility for a mood disorder, his doctor said in a statement released by the congressman's office Wednesday evening.

The statement said information about Jackson's treatment is protected by federal law and that the attending physician's name and treatment center will not be disclosed in order to protect (Jackson's) continuing privacy, the Chicago Tribune reported. 

Earlier, an NBC report said Jackson, 47, was being treated in Arizona for alcoholism, but after the report aired, Rick Bryant, Jackson's chief of staff, released an email statement saying that rumors about him being treated for alcohol or substance abuse (are) not true.

The statement quoted the unnamed Jackson doctor saying: The congressman is receiving intensive medical treatment at a residential treatment facility for a mood disorder. He is responding positively to treatment.

Earlier Wednesday, Chicago Alderwoman Sandi Jackson told the Tribune: I'm hopeful that my husband's doctors will be able to release something soon. I'm in constant talks with them about Jesse's condition and his medical prognosis going forward. 

She also told NBC Chicago her husband was not in rehab.

Jackson has been on a medical leave since June 10, but his aides and family have declined to disclose the nature of his medical problem, where he is being treated or when he may return to work.

Jackson's father, the Rev. Jesse Jackson, refused to talk about his son's condition during the annual conference of his Rainbow/PUSH coalition in Chicago Wednesday. 

Earlier Wednesday, the House minority whip urged Jackson to tell voters what is ailing him.

Let me just deal with this briefly in this way. I think Congressman Jackson and his office and his family would be well advised to advise the constituents of his condition, said Rep. Steny Hoyer, D-Md. He's obviously facing a health problem. We have many members who are out right now.

This is not an unusual circumstance. People get sick, and when people get sick, they miss work. Everybody in America understands that. But I think the family would be well advised to give his constituents as much information as is appropriate.