The "Liz & Dick" star must meet with a therapist at least three times a week until November 2014, Superior Court Judge James R. Dabney said, following the treatment recommendation of Richard Taite, founder and CEO of Cliffside Malibu, the rehab facility where Lohan was recently residing.
Taite wrote Dabney a letter stating the need for Lohan to remain in therapy.
"Our entire clinical team is in unanimous agreement that if these sessions are not required by the court and attendance verified once a month to ensure accountability, it is a setup for almost certain failure," Taite wrote.
The judge's ruling calls for Lohan to receive 18 months of therapy and gives her credit for the three months of rehab that she has just completed.
If the actress is traveling, she can meet with her therapist via videoconferencing software, the judge said.
Lohan, 27, was not present at the hearing meant to update Dabney on her progress.
The actress remains on probation for a pair of cases involving the theft of a necklace and lying to police about driving when her sports car slammed into a dump truck on Pacific Coast Highway in June 2012.
Taite praised Lohan's progress in recent months.
"We couldn't be happier with the progress Ms. Lohan has made in building a solid foundation from which to continue the excellent work she has begun here at Cliffside Malibu," he wrote.
Lohan started her treatment at the Betty Ford Center in Rancho Mirage and was later transferred to Cliffside Malibu. Her next court date is scheduled for November 2014.
The actress's latest film, "The Canyons" will have a limited theatrical release in New York and Los Angeles in August. She has signed a deal on OWN to appear in an eight-part series based on her life and will be interviewed by Oprah Winfrey in August.