The troubled actress - who was sentenced to a court-ordered 90-day rehab stint upon her release from jail earlier in the month - has now been discharged after spending just 22 days receiving treatment at the UCLA Medical Center.
Ed McPherson, her civil attorney confirmed: "She has been released from inpatient rehab."
It is believed the 24-year-old star left the facility via a back door on 24.08.10.
Lindsay was initially admitted to the treatment facility after she spent 13 days of a 90-day sentence behind bars for violating the conditions of her probation for a 2007 driving under influence (DUI) conviction.
The `Mean Girls` actress was ordered to undergo a three-month stint in rehab by Judge Marsha Revel, who was originally presiding over the case.
However, staff at the facility recommended the sentence was excessive, and advised she should be released from the clinic early.
Despite Lindsay`s father Michael Lohan repeatedly claiming she is addicted to various legal substances, doctors are said to believe she doesn`t have an "addiction".
An insider recently revealed: "Lindsay may have taken prescription medication, but she doesn`t have `an addiction`. She`s been through detox, but had no withdrawal symptoms, so doctors don`t believe her issues were as serious as they were led to believe initially."