The Hairspray actress, 28, has been placed on psychiatric hold where she will be held for 72 hours, according to TMZ.
The news comes after a difficult week for the troubled star, who was last year diagnosed with schizophrenia.
She retired from the public eye to study after being released from psychiatric hold and later released from rehab into the care of her mother.
Amanda flew to Los Angeles from New York on Friday (October 10) to meet her parents and was admitted to a treatment centre shortly after touching down in California.
Earlier that day, a series of disturbing tweets appeared on her Twitter page aimed at her parents. The former Nickelodeon child actress appeared to accuse her father of abusing her mentally and physically.
They have since been deleted.
The family's lawyer Tamar Arminak issued a statement in regards to the actress' accusations, saying: "My clients are heartbroken by these false accusations."
Amanda was arrested for driving under the influence of a controlled substance last month (September 28), effectively violating her probation.
She was placed on three years' probation in February and is expected to appear in court on October 23.
Reports say Amanda is engaged to teenager Caleb Pusey, who she met while in rehab at the Canyon Treatment Centre in Malibu.
What do you think of this story? Tell us in the comment box below.
Reveal is now on Google Plus! Join us here for the latest pictures, fashion and celebrity news!