(CNN) -- Rep. Jesse Jackson Jr. should take all the time he needs to get well now that his office has announced the Illinois Democrat is under treatment for a mood disorder, House Minority Leader Nancy Pelosi said Thursday.
Jackson, son of civil rights leader the Rev. Jesse Jackson, has not been on Capitol Hill since late May. In June, his office announced he was taking a leave of absence because he was suffering from a "medical condition."
Under pressure from some congressional leaders to disclose further details, Jackson's office on Wednesday announced he was "receiving intensive medical treatment at a residential treatment facility for a mood disorder."
Asked Thursday about Jackson's prolonged absence, Pelosi told reporters that the number of actual legislative days Jackson has missed -- when the House was in session -- totaled 12.
Pelosi, D-California, noted she had called this week for more information on Jackson's absence, adding that the Wednesday statement from Jackson's office "should enable him to have the ... time he needs to get well."
In Jackson's home district in Chicago, constituents told CNN affiliate WGN they wanted more details.
"You need to support your people. We supported you," said Ashley Hogams, while another woman, Charlene Endecavage, admitted to conflicting feelings.
"I think we need to leave him alone for the sake of his family, the children, his wife, but also we have a right to know," Endecavage said. With the November election in less than four months, "I wish they could share something with us as soon as possible," she added.
Jackson won a spirited Democratic primary earlier this year in his quest for a ninth full term in Congress and was considered the almost certain winner in his strongly Democratic district before he went on his leave of absence.
Jackson's illness comes as the House Ethics Committee is examining allegations that in 2008 he or one of his associates offered to raise funds for then-Illinois Gov. Rod Blagojevich in exchange for the Senate seat vacated by President Barack Obama going to Jackson.
Jackson has maintained his innocence and pledged to continue to cooperate with authorities.
"I did nothing illegal, unethical or inappropriate in that pursuit, and I believe that is what the Ethics Committee will conclude at the end of this process," he said.
In a separate incident, Jackson apologized to his constituents in September 2010 after the Chicago Sun-Times reported that a Chicago businessman told federal investigators that Jackson had asked him to pay for a restaurant hostess to fly between Washington and Chicago several times.
He said at the time he was "deeply sorry" that he had "disappointed some supporters."
In its statement Wednesday, Jackson's office noted that information on Jackson's status is protected by federal law, as is the information of all medical patients. At the same time, the congressman's office released what it said was a statement from Jackson's doctor. Jackson's office declined to give the doctor's name.
The doctor was quoted as saying Jackson "is responding positively to treatment and is expected to make a full recovery."
According to the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, "mood disorder" is a broad term covering a variety of neurobiological abnormalities that can include a major depressive episode, bipolar disorder and catatonia.
"Generally speaking, to be diagnosed with a mood disorder, your feelings must be intense, with the patient feeling either depressed, or having excessive energy for days at a time, where sleep is not needed and decision-making can be significantly hindered, or one can fluctuate between both extremes," said Nancy Molitor, a psychologist in private practice in Wilmette, Illinois, and assistant clinical professor of psychiatry and behavioral science at Northwestern University School of Medicine in Chicago.
Rep. Emanuel Cleaver, the chairman of the Congressional Black Caucus, told reporters Wednesday he has spoken several times with members of Jackson's "blood family" and is confident Jackson will return from his leave of absence.
Added Cleaver, D-Missouri: "He's fine. He's an old football player -- he'll be back."
Cleaver made it clear he is in regular contact with Jackson's family, not directly with Jackson himself.
Pressure began mounting on Jackson on Tuesday after comments to reporters in Chicago by Illinois Democratic Sen. Dick Durbin.
"As a public official ... there reaches a point when you have a responsibility to tell people what you're facing and how things are going," Durbin said, noting that Illinois Sen. Mark Kirk, who suffered a stroke, has provided updates on his progress as he continues to recover.
"Sen. Kirk has done that, and I think Congressman Jackson will face that, too," Durbin said.
CNN's Tom Cohen, Kate Bolduan, Deirdre Walsh and Jennifer Bixler contributed to this report.