As for the “mood disorder” he is suffering from, it could be one of four possible illnesses: depression, bipolar disorder, seasonal affective disorder, or mania. With Jackson being in an in-patient facility, and with very few details, it is not known how long it will be before he recovers or what type of treatment he could be receiving.

“Typically, the most effective way (of treating mood disorders) is through a combination of medications as well as therapy, whether it is psychotherapy or getting certain types of behavioral therapy to help you cope with your mood disorder symptoms,” said Dr. Tyeese Gaines, theGrio’s Health Editor. “If he’s in an in-patient center, it’s hard to say because we don’t know if his mood disorder is so bad that he’s in that facility or if he’s just there to keep everything private.

“When people are undergoing in-patient treatment, it’s usually because they’re not functioning at home at all. They’re not doing their daily things like getting up and showering and doing activities that we call daily living. The people who typically get admitted are either suicidal or homicidal.”

If Jackson is dealing with something as serious as major depression or bipolar disorder, it would keep him away from Congress for an indefinite period and could even cost him his spot on the ballot in November. Jackson, who is a heavy favorite to win re-election in Illinois’ 2^nd District, could be replaced by the state’s Democratic Party if he is deemed unfit to continue in the race or drops out.

“The party organization would select someone to take his place on the ballot, were he to withdraw,” said Ken Menzel, the Deputy General Council of the Illinois Board of Elections. “The party would do the selection, make a resolution, file the resolution with us with a statement of candidacy and then that person would go into the certification of the ballot.

“If this takes place by August 23, the party would simply have to fill the vacancy before then and we’d certify that new name. If we get past the 23^rd and we’ve already certified Congressman Jackson, if he were to withdraw after that time – and it was 15 days before the election – the party would have an eight-day window to fill the vacancy and we would do an amended certification.”

Jackson’s absence has confused and even angered his constituents, who have been left to speculate why he disappeared from sight. Some are even questioning the validity of his illness.

“There are a lot of politicians about go to jail soon for their involvement with Blagojevich or other shady (stuff) that they were into,” said Sean Moore, who lives on Chicago’s South Side. “Jackson is the prime target, so he’s setting up his insanity defense. There are multiple mood disorders, what’s the exact name of his? He basically had his doctors make some (stuff) up that you really can’t prove, to start his defense. I personally think it is genius.”

Jackson’s absence has created doubts across the South Side of Chicago, along with its neighboring suburbs. The amount of skepticism among his constituents could lead to future issues, especially after having already survived a tough primary fight with Halvorson this year.

“I think his absence might be more important in the abstract, from a democratic-theory perspective,” said Jeff Jenkins, an associate Political Science professor at the University of Virginia. Jenkins dealt with Chicago politics while teaching at Northwestern University.

“Right now, his district constituents don’t have a voice in the House. We live in a system of representative democracy, and (due to his absence) the citizens of his district lack such a representative voice.”

Follow Jay Scott Smith on Twitter @JayScottSmith