The 'Liz & Dick' actress is currently at the Betty Ford Clinic in California - with another three months left on her 90-day court-ordered stay - and friends worry she is lacking "energy" since her Adderall was taken away.
The troubled star has had the medication - which she has claimed is to treat her ADD (Attention Deficit Disorder) - stopped by doctors at the clinic and those close to her think it's harming her progress.
An insider told RadarOnline.com: "Lindsay just doesn't want to be there. She was forced to go to Betty Ford by the judge instead of going to jail.
"The actress looks extremely haggard, her face is bloated, and it doesn't look like she has brushed her hair in days.
"She looks very dishevelled and has absolutely no energy since docs took away the Adderall."
It is said Lindsay, 26, has to accept the rehabilitation process to benefit from it, rather than letting herself go "through the motions".
The source added: "[Until she] surrenders to the recovery process, she will never have a shot of sobriety.
"To Lindsay, rehab is just a revolving door, and she is just going through the motions, pro forma."