She is in rehab and court again because her recent drug use violated her probation.
The decision by Judge Elden Fox means that Lohan will remain in rehab at least until January 3, and will then be subject to random drug testing until her next court date on February 25.
'You are an addict. I hope you understand that,' Fox told Lohan, according to celebrity website TMZ.com.
Lohan, 24, voluntarily checked in to the Betty Ford rehab centre in southern California last month after she failed several drug tests in violation of her probation conditions that banned her from using drugs and alcohol.
Lohan served 90 days in jail and court-ordered rehab earlier this year for parole violations stemming from drunk-driving offences.