The insider said Moore, 49, checked into the facility after she was hospitalized Jan. 23 for seizure-like symptoms she suffered during a party at her home in the Benedict Canyon area of Los Angeles. Some media reports alleged she fell ill after getting high off of nitrous-oxide inhalers called whip-its.
The star of "Margin Call," "Ghost," "About Last Night" and "St. Elmo's Fire" is the mother of three grown daughters with her ex-husband, film star Bruce Willis. Her marriage to actor Ashton Kutcher recently ended.
"She's on total lock-down and only talking to a small group of people," an insider told E! News during the weekend, adding Moore is being treated for an eating disorder and addiction issues. "It became clear to her that her way of coping with her stress was not working and she needed more help."
E! News said Moore's representative could not be reached for comment.