Drug Benders & Failed Comebacks: Inside Mischa Barton's Downward Spiral

Mischa Barton was rushed to the hospital for a mental evaluation after cops were called to her home on Thursday, but according to sources, the starlet's big scare is no surprise.

"Mischa has been on this downward spiral for years now," an insider told RadarOnline.com exclusively. "Her attempts at getting healthy have always failed. She took on Dancing With The Stars to make some money and try to clean up her act — but that didn't help."

"She ended up purposely getting booted off the show because she couldn't handle it. She hated the show, she hated the work involved and really wanted to keep partying," the source added.

As reported, the 31-year-old was reportedly spotted in her backyard hanging over the fence, babbling about her mother and spitting out "incoherent statements."

Brighter Days! Selma Blair Bags New Man After Airplane Meltdown

Her concerned neighbors called 9-1-1 and the Sheriff’s deputies and firefighters responded. The neighbors reported it was a jumper or a possible overdose.

But this incident is just one of many.

"I was with her a few times in the past year or so. One time was at a dinner party and she was doing mushrooms! Not the kind you eat either. Who does shrooms at a dinner party?" the insider revealed. "Then, just two weeks later, she was at a bar in NYC and smoking pot and doing coke. She was openly using her hand to snort coke off of in this tiny space."

Now, those close to Barton hope she'll finally get her act together following her hospital visit.

"I really hope this is THE wake up call she needs," said RadarOnline.com's source. "She has a horrible relationship with her mom — she's pretty much alone in LA. She's broke and hasn't been able to get it together to start making money again. Every time she attempts any sort of come back she ends up shooting herself in the foot and not being able to follow through."

‘Zip Me Up Before You Go Go’ Vice Cop Who Busted George Michael In L.A. Bathroom Still Haunted By ‘Lewd’ Act Arrest

"It's not just the partying either," the insider added. "She struggles with depression and she self medicated with the partying so when she hits bottom she hits hard."

Barton was transported to the hospital voluntarily. She was previously held on an involuntary hold in a hospital in 2009, but later said it was a bad reaction to a wisdom tooth removal.