Mischa Barton has been detained under “involuntary psychiatric hold” for her own safety at a Los Angeles hospital.

The 23-year-old actress, who is a regular on the London party scene, has been held under Section 5150 of the California Welfare and Institutions Code — the same code that hospitalised Britney Spears twice in 2008.

The section says authorities can hold a person against their will for up to 72 hours if they present a danger to themselves or others, are gravely disabled or suffer from a mental disorder.

“Medical issue”: Mischa Barton is being held in hospital

The OC star was forced to miss the New York premiere of her new film The Homecoming after she was admitted to the Cedars Sinai hospital in LA on Wednesday.

Police arrived at her West Hollywood apartment after responding to a non-emergency call to assist with a “medical issue”.

LAPD spokesperson April Harding said: “We responded to her home last night on a medical issue. We assisted with it. She was removed from her home.”

When asked if Mischa was co-operative, the officer answered: “I guess.”

Fears: Barton is being detained under the same welfare code that restrained Britney Spears last year

A statement from her representative confirmed Mischa was receiving hospital care but declined to give further details.

A friend of the London-born star told US magazine People that she had been troubled for several months.

The pal said: “She has been dealing with a lot of personal issues.”

The Homecoming producer Austin Stark said: “It's obvious we'd like her to support the movie and be here but we hope she gets better.”

Mischa was last year charged with driving under the influence of alcohol and possessing marijuana. She was sentenced to 36 months probation and went into rehab.

Only two weeks ago, The Eye revealed she was thrown of out the ladies toilets of London nightclub Whisky Mist after she tried to bring one of her friends into the loo cubicle with her.