The celebrity news website described the move as shocking, since the rehab does not have the psychiatric resources available at UCLA.
The 27-year-old actress was hospitalized on an involuntary hold and treated for an undisclosed mental illness since July. However, she reportedly wasn't making tremendous progress before she moved to the rehab three weeks ago, TMZ said.
The former child star was placed on an involuntary psychiatric hold after she allegedly caused a disturbance when she tried to break into a retirement community in her hometown of Thousand Oaks, Calif.
The following night, she allegedly set a small fire in a driveway, which led to police involvement and her eventual hospitalization.
The actress is known for her work on TV's "What I Like About You" and "The Amanda Show," as well as in the films "What a Girl Wants" and "Hairspray." Her most recent major screen credit was a supporting role in 2010's "Easy A."
Her once-bright career has been eclipsed in recent years by her bizarre Twitter rants and frequent brushes with the law.