The Tribune attributes the news to Jackson's brother Jonathan Jackson, while the Sun-Times attributes it to "a source close to Jackson."
Jackson, who just won reelection in his Chicago district, has been dogged by controversy. First he took months of medical leave without giving a prompt explanation as to why and then federal authorities announced they were investigating whether Jackson misused campaign dollars to decorate his Washington, D.C. home.
Jackson, his doctors finally revealed, was suffering from bipolar II, "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."
The Tribune adds:
"Although he did not wage a campaign, Jackson won re-election on Nov. 6 to another two-year term in the House by defeating a Republican and independent challenger. Under Illinois law, Gov. Pat Quinn, a fellow Democrat, would call a special election to fill Jackson's 2nd District congressional seat, which extends from Chicago's South Side to Kankakee.
"He is the son of the Rev. Jesse Jackson, the civil rights leader, and the husband of Chicago Ald. Sandi Jackson, 7th."
We'll have more on this story as it unfolds.