Mischa Barton was submitted involuntarily to a California mental health facility last week, and she’s still there. According to insiders, friends and associates have been trying to get Mischa into some sort of treatment for months, including party pal Lindsay Lohan.

The two club regulars often partied together into the early morning hours. But last year, Lindsay walked away from the friendship after a messy Mischa pushed Lindsay over the edge. Sources close to Lohan tell Fox 411 that the two girls haven’t spoken for months, but Lindsay would help Mischa if she asked for help to get through this latest fiasco.

“Lindsay and Mischa used to go out all the time together in Los Angeles. They were like kindred spirits when it came to clubbing and letting loose,” says the insider. “ They have many mutual friends, but everything shifted for Lindsay last year at a party. Mischa was completely out of control, and Lindsay sat Mischa down then to make it clear that she needed help. Lindsay was desperate for Mischa to clean herself up and offered a treatment facility and a therapist to help Mischa. Mischa completely ignored Lindsay, and that was the end.”

Several people close to the “OC” actress tell FOX411 she’s been on a downward spiral for years. “No one close to her is surprised,” says one pal. “Alcohol was like the gateway to other things for Mischa. Nobody has been able to stop her until now. Hopefully this psychiatric hold will force her to seek real help.”

Mischa’s latest stylist deserted her as well, says the insider, warning that ”Mischa must get help or she will be all alone. She can’t continue down the path of the last two years or so. It’s destructive and it will end her career for good.”

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