Lohan signed her discharge papers from the facility on her 22nd day of treatment and left the building by the back door, where a limousine was waiting, the Web site said.
The 24-year-old star of "Freaky Friday" and "Mean Girls" spent nearly two weeks this summer in a solitary jail cell for violating probation in a 2007 driving-under-the-influence case. Her 90-day sentence was cut short because of good behavior and jail overcrowding.
Lohan -- who has long battled addiction to drugs and alcohol -- had been at the drug treatment facility since her Aug. 2 release from jail.
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