Court documents: Lindsay Lohan tested positive for alcohol after rehab

(CBS) Lindsay Lohan failed an alcohol test on Feb. 8, 2011, about a month after she completed court-mandated rehab at the Betty Ford Center, according to a probation report.

The report also claims that the actress, 24, was drinking the night she scuffled with a Betty Ford employee in December, citing local police interviews with restaurant, hotel and nightclub employees.

Pictures: Lindsay Lohan
Pictures: Lohan charged with theft

Charges that she battered a rehab employee that night were dropped in March, due to lack of evidence.

The probation report was released Wednesday, after Lohan pleaded no contest to misdemeanor grand theft of a $2,500 necklace. The report states that the actress "has been suspected of similar conduct in other jewelry stores," but no charges were ever filed.

"The probation officer believes that substance abuse is the root of the defendant's problems," the report states, though Los Angeles Superior Court Judge Stephanie Sautner disagreed with that assessment during Wednesday's hearing (which the actress was not present for).

"She has other problems, which she self-medicates," the judge said.

Lohan was ordered to undergo psychological counseling and complete a shoplifters' alternative class, in addition to the 120-day jail sentence and 480 hours of community service that she was previously sentenced to for violating her probation.

She must report to begin serving time by June 17. It's expected she'll be allowed to serve out her jail sentence under house arrest because she is a non-violent offender. A Los Angeles County Sheriff's Department spokesman told the Los Angeles Times that Lohan's sentence would likely be reduced because of good behavior and jail overcrowding.