Lindsay Lohan agreed to a 90-day stint in a lockdown rehabilitation facility last month as part of her plea deal with Los Angeles prosecutors, who had charged her with reckless driving and lying to police.
But Lohan reportedly made sure she could take her Adderall with her.
According to TMZ, Lohan was "steadfast" about her need for Adderall -- a prescription drug used to treat attention deficit hyperactivity disorder (ADHD) -- during negotiations, and would have taken the case to trial without it.
Lohan received an Adderall prescription while serving jail time in 2010, and sources told the gossip site that the 26-year-old starlet believes she can't function without it.
Ahead of her May 2 rehab start date, Lohan has been fulfilling promotional obligations in Sao Paulo, Brazil, where she was photographed hiding from fans under a nightclub table.