The Detroit Free Press Friday described how Marshall Mathers -- the rapper's real name -- fought insomnia throughout his five-week Anger Management 3 tour, which wrapped up last weekend in Detroit.
Sources told the Free Press Mathers reached a point during the tour where he was only getting about an hour of sleep per night.
A relative told the newspaper insomnia runs through the maternal side of the rapper's family.
"We don't require much rest, so we tend to go until we drop," the family member said. "Kind of like racehorses, racing until falling over."
As he grew more tired during the tour, sources said Mathers increased his dose of the legal prescription. But, higher doses of Ambien have the opposite effect -- they will keep the insomniac awake instead of inducing sleep, the Free Press said.
After meeting with friends and associates at his suburban Detroit estate Monday, Mathers decided to check himself into the hospital. A day later, it was announced he was canceling his European tour because of "exhaustion complicated by other medical issues."