More than a month after he took an unexplained leave of absence, it’s still not clear what’s ailing Illinois Representative Jesse Jackson, Jr.

A statement released by the congressman’s staff Wednesday indicated he is being treated for a “mood disorder,” though the statement offered little clarity about his precise condition. The statement read:

Information regarding the Congressman’s treatment is protected by federal law under the privacy provisions of the Health Insurance Portability and Accountability Act of 1996 (“HIPPA”). The name of the attending physician and treatment center will not be disclosed in order to protect his continuing privacy.  His physician makes the following statement:

“The Congressman is receiving intensive medical treatment at a residential treatment facility for a mood disorder.  He is responding positively to treatment and is expected to make a full recovery.”

In addition, the rumors about him being treated for alcohol or substance abuse is not true.

Pressure has been building on the Congressman to inform Democratic leaders, and Jackson’s constituents, about the full facts of his condition. A Democratic Capitol Hill staffer told theGrio Wednesday that Jackson had not confided in fellow members of Congress, members of the Congressional Black Caucus, nor, to their knowledge, Democratic leaders in the House that he would be taking a leave, for what reason, or for how long.

WATCH: NBC Nightly News coverage of the Jesse Jackson Jr. saga

NBC News reported late Wednesday that friends and colleagues of the 47-year-old son of civil rights leader Rev. Jesse Jackson, have indicated he has been at a residential treatment center in Arizona. NBC’s Andrea Mitchell reports:

A family friend who is in close touch with Jackson’s parents says the congressman is suffering from “severe clinical depression” and has an alcohol problem – although his wife and staff have a different view of his condition.

His wife, Sandi Jackson, texted NBC Chicago on Wednesday saying that her husband is “not in rehab.”

Jackson has been on medical leave since June 10, but the public did not learn about it until weeks later. His office initially told the media Jackson was being treated for exhaustion.

Read more on this story on NBC Politics.