Mischa Barton is derailing faster than you can say rehab. The 23-year-old star of The Beautiful Life may say she’s doing great, but friends admit that things aren’t going so smoothly for the actress. During Mercedes-Benz Fashion Week in New York, Mischa (who was hospitalized in July on an involuntary psychiatric hold) was partying one night after the other, while shooting her show during the day.

“Mischa is drinking and letting loose as if the medical treatment this summer never happened,” a friend tells BettyConfidential. “She is in denial that she has any problem at all, especially when it comes to partying, but her mom is staying with her around the clock.”

Friends warn that Mischa and her mom, Nuala, may be spending a lot of time together, but they are not necessarily seeing eye-to-eye. “They argue a lot and early last week had a blowout fight at Mischa’s hotel. Mischa wanted to go out and party and her mom was not happy about it at all but since she’s an adult there’s very little she can do to stop her.”

Spies at the Style 360 What Goes Around Comes Around party in SoHo witnessed drinking and strange behavior from the CW star. “Mischa spoke in a British accent to everyone she didn’t know. She would not drop the accent until her friends were with her. When she was only speaking to them, she would speak in a very New York accented voice. It was so strange!”

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