The troubled actress who is staying at the Betty Ford Clinic in Los Angeles, had voluntarily entered into a substance abuse program there, reported New York Post online.
The 24-year-old is also trying to cut down her phone usage and the staff are now helping her to reduce the amount of time she spends on social networking websites.
"Lindsay is only allowed to use her phone for two hours a day, and only to keep in touch with family and close friends. Before, she would repeatedly and compulsively email her friends if she was ever in a situation where she felt lonely, and she would vent on Twitter," said a source in the rehab centre.
The policy has been implemented so Lohan can "concentrate on herself" during therapy. The actress is due in court on October 22 for a probation hearing, after she failed two drugs tests last month.
Lohan, who served 13 days of a 90-day jail term behind bars in July, returned to prison following the failed tests, but ended up spending just a matter of hours behind bars after posting USD 300,000 bail.