Steven Spielberg is to question the integrity of America's most celebrated president in his forthcoming biopic of Abraham Lincoln, according to a report in the Sunday Times. Spielberg's movie, to be adapted from a biography by the Harvard professor Doris Kearns Goodwin, will portray "Honest Abe" as a manic depressive racist blighted by marital problems.

Spielberg is said to identify with Lincoln, who, like the director, was tormented by stress and medical problems. "This is a project close to his heart," says a source at his studio, DreamWorks. "But he is not interested in a sugary confection."

Goodwin - whose previous works include Lyndon Johnson and the American Dream and The Fitzgeralds and the Kennedys: An American Saga - believes the fondly held view of Lincoln as a moral crusader and devout family man is unsustainable. "There's more to say, not all palatable to the American public who like their saints saintly."

According to the Sunday Times, White House papers show that the "Great Emancipator" did not start the American civil war intending to free the country's 3.5m slaves. By modern standards he was racist, claiming in private that black people were "morally inferior" and that they should be "pack[ed] back to Africa where they will not cause us any more problems."

Spielberg's Saving Private Ryan and Amistad have both been subject to allegations of historical inaccuracy. If the Lincoln biopic is as confrontational as suggested - and, given Spielberg's pedigree of dewy-eyed patriotism, there may be reason to doubt that - more controversy will surely follow. Before work begins on the presidential pic (expected in the autumn), Spielberg must complete work on his current projects, A.I., with Jude Law, and Minority Report, with Tom Cruise.