Documents released on Tuesday said that McCall "presents an imminent danger to [him]self or others as a result of mental illness or is so seriously mentally ill as to be substantially unable to care for [him]self."
McCall was evaluated by a mental health expert, who testified at a detention hearing on Saturday night that McCall was mentally ill and in need of hospitalisation. An involuntary commitment hearing is planned to determine whether he should be held for further observation and evaluation.
McCall was placed on 18 months probation in December after pleading guilty to possession of marijuana and cocaine in Illinois. He was also arrested in North Carolina in early April 1996 and charged with marijuana possession.
McCall spent time at a North Carolina drug rehabilitation centre in August, and at the time his manager, Jimmy Adams, said he was being treated for marijuana and cocaine abuse. "Drugs took over his life, and now he's trying to take his life back," Adams said then.
McCall won the World Boxing Council heavyweight title in September 1994 after a second-round knockout of Lennox Lewis. After a successful defence against Larry Holmes, he lost to Frank Bruno in September 1995.
In February this year, McCall broke down in tears during a title fight with Lewis. His purse from the fight is still being withheld, pending an investigation into why he stopped throwing punches and defending himself.
After the fourth round, he stood and cried in his corner and the referee stopped the fight 55 seconds into the fifth round.