Mischa Barton was hospitalized in Los Angeles on Thursday, after displaying erratic behavior.
The LAPD tells ET that they received a disturbance call at 7:15 a.m. on Thursday morning, for a female that was "yelling and screaming."
"Upon arrival, deputies located the female victim who was fully clothed sitting on a couch," Sergeant Duncan of the L.A. County Sheriff Department's West Hollywood station says. "The female was making incoherent statements. Soon after deputies arrived, the female voluntarily was transported by Los Angeles County Fire to a nearby hospital."
WATCH: Mischa Barton's 'Slightly Sedated' 'Dancing With the Stars' Debut Earns Her One of the Lowest Scores of the Premiere
LA County Fire tells ET that they received a call from the sheriff's office on Thursday and was on scene in West Hollywood at 7:35 a.m. for a "behavioral call." LA County Fire says the incident was a "psych rescue," and that there was "a possibility of an overdose" with the female victim on the scene.
Barton was hanging over her backyard fence in West Hollywood, and rambling about her mom being a witch, Ziggy Stardust, as well as the world shattering before she was hospitalized for mental evaluation, TMZ reports. According to photos, the 31-year-old former The O.C. star was wearing just a white dress shirt and tie at the time.
In July 2009, Barton was placed under a 5150 involuntary psychiatric hold for two weeks after seeking medical attention for a tooth infection.
Barton talked about the difficulties of being a child star in 2014. "It's tough. It's really tough when you are young in this business," she told Metro U.K. "People blow a lot of hot air at you. That's the main thing. Keep your head on your shoulders -- even when you think your head is on your shoulders, sometimes it isn't!"
NEWS: Mischa Barton Compares 'Dancing With the Stars' Stint to 'The Hunger Games': 'It Was Awful'
ET last spoke to the actress in November, when she happily promoted Esquire Network's car enthusiast show, Joyride, in which she was one of four celebrity co-hosts. Barton told ET that she was hoping to get into the producing side of the TV business, and already had a project she was working on with a close pal.
"I'm trying not to work too, too much and do projects that I’m passionate about and also get some of this producing stuff off the ground -- that’s where I'm at personally," Barton said of her career. "That's why it was so fun to do [Joyride] at the end of the summer. These are my passions. I'm now getting into my 30s and it’s fun to sit back and choose more carefully the roles I want to do moving forward and have a lot more fun with it."