LOS ANGELES — Slumped on the sofa at a private house party in Malibu, Lindsay Lohan reaches clumsily for her bag. Her artificially plumped lips parted company with their last cigarette several minutes ago, and she’s clearly in need of a nicotine fix.

Fumbling among the detritus in her designer tote, she pulls out a box of Parliament Lights and a tattered notebook, and begins scribbling pensively.

“I write absolutely everything down,” she tells a partygoer after asking him for a light. “It’s the only way I can make sense of everything that happens in my life.”

While the ramblings of the child star-turned-absentee morgue cleaner would no doubt make for fascinating reading, many would find her thought processes harder to decipher than the Dead Sea Scrolls.

“To say she’s delusional would be a major understatement,” one former associate tells The Post. “She genuinely seems clueless as to why these things keep happening to her. There is always something, or someone, else to blame.”

Just Wednesday, Lindsay was led from the Los Angeles County Superior Court in handcuffs and ordered to post $100,000 bail after Judge Stephanie Sautner angrily stated that Lohan had violated the terms of probation in her misdemeanor shoplifting case by failing to show up for community service at a women’s shelter on no fewer than nine occasions.

The following day, Lohan showed up 40 minutes late for court-ordered morgue cleaning at the Los Angeles County coroner’s office and was considered a no-show.

Lindsay, 25, is due back in court on Nov. 2, when it will be decided if she should face time behind bars.

Dubbed “uninsurable” by the producers of “Inferno,” who fired her from the Linda Lovelace biopic last year, Lindsay’s latest venture — a $500,000 modeling gig for German designer Philipp Plein — is hanging in the balance. Reports last year claimed the actress was more than $600,000 in debt (her mom, Dina, denied the story), but “cutbacks” are not on Lindsay’s agenda.

“Lindsay gets by on checks from club appearances, and from plugging firms on her Twitter account and Web site,” a Lohan insider reveals. “The amounts are nothing like what she used to command, but she also gets a lot of things for free: She’s not shy of clearing the shelves at a gifting suite.

“She doesn’t really understand the value of money; she hoards hundreds of thousands of dollars worth of shoes and clothes in her apartment, but she won’t sell anything to help clear her debts.”

Lindsay’s friend choices are questionable at best.

“If someone disagrees with her, or tells her she’s out of line, she cuts them dead,” the acquaintance says. “She is surrounded by sycophants who are hanging on the coattails of her notoriety; she is still very naïve and trusting and she gets exploited a lot.”

But how did the feted young actress plummet from A-list to ”lost cause” status? One friend says it was all in her upbringing.

“She has been exploited for most of her life,” the pal says, “so it’s unsurprising she doesn’t have much grip on reality.”