Reports regarding the dire health of Lindsay Lohan are stacking up, with some insiders suggesting that the troubled actress is on the verge of a complete breakdown. And even though the 23-year-old is still larger than life when it comes to the LA nightlife scene, her frame seems to be disappearing before our very eyes.

While Lohan appeared to be a healthy size at the recent Nokia X6 launch party, just days later at Paris Fashion Week, she showed up looking shockingly gaunt.

According to a health expert, those constant fluctuations could be seriously detrimental to her health.

“This is dangerous both physically and psychologically,” LA-based psychologist Dr. James E. Walton said. “This behavior mimics the behavior of those people who are experiencing the negative effect of drug and/or alcohol abuse. They lose sight of any accurate form of self-observation. It only takes one bad decision to end up in a disastrous situation.”

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She's also smoking up a storm, which she has documented via her Twitter page in recent weeks. From photos of her with a cigarette in her mouth to Tweets about her brand preferences, it seems that Lohan has found a new favorite vice.

At Perez Hilton’s birthday bash last weekend, she had to be told by party organizers to put out her cigarette inside. But just moments later, she lit up again as Liza Minnelli took to the stage to perform.

But it wasn’t only her blatant disregard for party rules that raised eyebrows at Perez’s bash. One partygoer complained to us that Lohan, who spent the night nervously covering her face with her ratty hair, was in desperate need of a shower.

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And the strange behavior didn’t end there. She arrived at the bash in a sparkly turquoise dress but was quick to change into a tight black lingerie-like frock inside.

When Pop Tarts stopped to chat with her, she professed her love for Hilton, who devotes countless posts on his blog to bashing the starlet.

“Perez always tries to hate on me but I love him as a person and he's wearing a Chanel inspired suit!” a not-exactly-with-it Lohan told us, eyes squinting.

Then, there was the much-talked-about white powder that was found on her shoes (and the hands of one of her male pals) later that night as she exited the event.

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If this all doesn’t sound strange enough, we’re also told Lohan’s behavior when she is out with friends has become even more erratic over recent weeks. Lohan’s estranged father Michael even held a press conference on Tuesday to address the well-being of his daughter.

“Lindsay is not okay. I think we’ve all seen that and we know that. I’ve tried every possible way to reach out to my daughter; no one can turn their backs on it anymore. It’s a lot worse than people can imagine,” Lohan said. “Lindsay needs help now. Sometimes we don’t know when we hit rock bottom… but it is all about admitting the truth to ourselves and the people around us. Life is tough; I don’t want it to be short for her.”

Lohan added that he intends to sit down privately with Lindsay and an attorney to discuss a plan of action.

A rep for Lohan did not respond for comment.