The Inside Story: Mischa Barton's War with Her Manager Mom

Long before Mischa Barton filed a lawsuit against her mother, tensions between the two had threatened to boil over.

The actress, 29, has had a rocky relationship with her manager mom, Nuala, particularly after Mischa’s fame exploded as a teen star on Fox’s The O.C.

“Mischa was the bread and butter for her entire family,” a former associate of Barton’s told PEOPLE in 2013. “But her mom was running the show.”

Then dating oil heir Brandon Davis, “Mischa had intense conflicting opinions coming at her,” the former associate said. “She had a boyfriend telling her one thing. She had a mom telling her another thing. And like any momager situation, Mischa is paying the rent. They bought this huge house in California, which was probably a bit of a stretch for them.”

The house would later go into foreclosure, with documents revealing that the actress was nearly five months behind on her mortgage payments in August 2014.

Despite all the turmoil, Barton was protective of her mom in a wide-ranging 2013 interview with PEOPLE.

“My mom is a real survivor,” she said in 2013. “She’s a very strong woman. I think that’s where I get it from.”

Now Barton alleges that Nuala stole money to buy a $7.8 million Beverly Hills mansion, which she is “using as her ATM,” says Barton’s lawyer, Alex Weingarten.

Weingarten says Barton is “locked out” of the house, which Nuala is sharing with Barton’s father, Paul, and “can’t even visit her dog.”

(Efforts to reach Nuala have been unsuccessful.)

Mischa was just 5 years old when her family moved from the United Kingdom to New York City to help foster her fledgling acting career – a move that sparked culture shock for her mother.

“My poor mom, being thrust into New York with us when we were very young,” Barton, who has two sisters, told PEOPLE in 2013.

Later, when the family moved to Los Angeles as Barton’s television career took off, “nothing could prepare them to have their children jump into the overtly sexualized and crazy world of L.A.,” she said.

At 16, Barton landed the lead role of Marissa Cooper on The O.C. and quickly rocketed to fame, living a “jet-set lifestyle,” as she put it, and partying in the same circles as Lindsay Lohan and Nicole Richie.

“It was a train I could not get off of,” she told PEOPLE of the events that led to the 2009 “full-on breakdown” that rocked her health and her career. (She was briefly committed to a psych ward for what she later said were unfounded fears that she was suicidal.)

Barton cautiously defended her mother in 2013. Asked whether Nuala could have done anything to protect her from the personal turmoil she struggled with, she replied, “I think that everybody at the time did what they thought was best, and I think that’s the only way I could put it. You have to understand that I come from a very Irish, English family, and they were thrust into a situation completely foreign to them.

“I think what’s important at the end of the day as you get older is to sit back and realize people really do have the best of intentions,” she said. “You take the chain of events as they come.”

• Reporting by ELIZABETH MCNEIL and MELODY CHIU