"She's just so happy to be out of jail," says a source close to the actress. "But she also has a lot of anxiety about treatment and what it will be like. Being there for 90 days is scary to her, and, she thinks, way too long."
However Lohan may be feeling, the staff at UCLA's Resnick Neuropsychiatric Hospital – where the troubled star, 24, is reportedly undergoing treatment for both psychological and addiction issues – has seen it all before. They also happen to be one of the most widely respected addiction treatment and research operations in the country.
"She will be neither unique nor the usual thing there," says a source intimate with the program. Both patients and employees refer to the program as "4 East," after the floor on which a majority of the treatments take place and the building in which it is housed, Resnick East.
"They will customize a program to help her with whatever she is going through," adds the source. "Everyone there is treated differently."
Rules and RegulationsBut Lohan shouldn't expect special treatment. Celebrities who have gone through the program in the past have mixed freely with the other patients, and there will be plenty of rules that will take quite a bit of adjustment.
Tops on that list: the strict ban on cell phones, which will mean no texting, Tweeting, or Internet.
On the other hand, Lohan will be able to make and receive phone calls – she will just have to do so on a payphone in the common area. She won't have privacy from the other patients or staff, and she won't be able to talk all day.
"The general rule is no more than 15 minutes," says a former patient.
The facility also restricts most makeup and any clothing with ties or belts, including shoes with shoelaces.
While Lohan will have limited mobility around the facility – most patients cannot leave the fourth floor – friends and family will be free to come and go during visiting hours. (Lohan had several visitors during her 13 days in jail.)
Piecing it TogetherRecreation at 4 East will also be a little different from what Lohan is used to. "We do puzzles together all day long – parrots, dolphins, landscapes," says the former patient. "It's our primary form of entertainment."
The star will also have plenty of board games from which to choose, and most rooms have flat-screen TVs. She will also be allowed to light up on a smoking patio, which is the one place where patients from different programs interact freely.
Getting BetterBut Lohan will not be in treatment just to mingle or play games. Her intensive and customized treatment will likely include personal and group therapies, strictly administered medications, occupational therapy and creative outlets to express her emotions.
"It's kind of like arts and crafts – decoupage, collage, painting," says the former patient. "She'll have different ways to express how she is feeling."
The doctors helping her recover will be some of the best in the country, and she will receive cutting-edge therapies and plenty of focused attention. "They have done groundbreaking work both on medications and psychotherapies for addiction," Keith Humphreys, professor of Psychiatry and Behavioral Sciences at the Stanford School of Medicine, tells PEOPLE.
But will it work for Lohan?
"Jail was a big time wake-up call, but now that it's over, rehab will really be the only thing that'll get to her deeper issues and teach her to change for good," says the Lohan source. "That's what everyone is waiting to see."
With additional reporting by LORENZO BENET and JENNIFER GARCIA