For three years, Showtime’s “Weeds,” which kicked off its fourth season last night, has tried, sometimes successfully, to be funny and subversive in a deadpan, hipster way. But at last it has grown weary of trying to impress what’s left of the bourgeoisie, and now it is attempting to be evil in a deadpan, hipster way.

It’s as if Jenji Kohan, the show’s creator, were performing an experiment on America’s high-end cable audience: “How vicious and sick can I make this series and still win approving notices from the critics and an audience sizable enough to keep my paymasters happy?”

If that sounds a bit strong, wait until episode three of the new season, in which several characters toy with the idea of euthanizing an old woman — an Auschwitz survivor, no less. It is theoretically in the name of compassion, though the notion that anybody harbors any compassionate feelings for her is utterly undermined by the script, which submits her to a barrage of degrading, dehumanizing jokes and comments.

Up to now, “Weeds” has taken place in Agrestic, a fictional suburb in Southern California. But Agrestic has been devoured by a fire, and Nancy Botwin (Mary-Louise Parker), the terminally cute, drug-dealing mother of two teenage boys, Silas (Hunter Parrish) and Shane (Alexander Gould), along with her feckless brother-in-law, Andy (Justin Kirk), has abandoned her house full of marijuana plants (in fact, she burned it down herself, after dousing it in petrol) and moved operations to a seaside town just north of Mexico. In partnership with Guillermo (Guillermo Diaz), a thuggish member of a Mexican drug cartel, she has decided to enter the big leagues, which means frequent border crossings and raised criminal stakes.

It also means persuading Lenny Botwin (Albert Brooks), her late husband’s father, who lives just north of the Mexican border with his ailing mother, to put them up while they avoid a credit-card trail and the attention of the police. But first they have to get there, and at a pit stop during last night’s episode, Ms. Kohan indulged in her trademark penchant for needless obscenity. Coming back from the restroom, Andy reported that he had just seen the best bit of graffiti ever, and then recited it: “Here I sit / Cheeks a’flexin’ / Giving birth / To a baby Texan.” In the meantime, Nancy complained that a bird was trying to defecate on her head.

While this was going on, Nancy’s sometime friend, Celia (Elizabeth Perkins), was jailed for Nancy’s crimes, and Dean (Andy Milder) and Doug (Kevin Nealon), two of the show’s stalwarts, were still in Agrestic, stoned out of their minds in an alley while flakes of burning ash dropped from the sky. In one scene, Doug said it was “snowing in SoCal,” except that the snowflakes were warm. They tasted “like loss,” he said ” — or muffins.” “Mine taste like a vinyl sofa,” Dean claimed.

Ms. Kohan once stated that “Weeds” was about real people in a fake setting, but there’s very little that’s “real” about her characters, however sterile Agrestic may be. It’s true, Doug and Dean, performing their little comedy routine for the umpteenth time, do act like “real” people who are stoned. They act like real people who are stoned who know they’re on television, and are reciting someone else’s lines while surrounded by a film crew.

But surely, with the great Albert Brooks on-screen, we have something to look forward to? (He guest stars for the first four episodes.) Sadly, no. Mr. Brooks plays a whiny, dissolute gambler whose only good deed is to take care of his mother, who is in a coma and hooked up to a life-support machine in his living room. He’s not at all happy to have guests — even family ones.

“How long does it take Portnoy up there to finish his business?” Lenny asks, referring to one of his teenage grandchildren.

“Use the downstairs bathroom,” Andy retorts.

“I don’t like the toilet in there,” Lenny complains. “It’s got a padded seat. It’s like taking a s— on a mushroom.”

Andy remains unimpressed. “I’ve taken a s— on mushrooms,” he says. “And on a mushroom, actually.”

To which Lenny replies, “Of course you have.”

There’s no topping these people. When, before the euthanasia scene in the third episode, Nancy announces that she needs “to go kill my dead husband’s grandmother now,” another character immediately comes back with a jaded, “Been there.”

What Ms. Kohan produces is the pseudo-satire of a spoiled narcissist, and it becomes progressively harder to swallow the longer the series goes on. Next week’s episode features Nancy’s first drug run across the Mexican border, complete with a satirical riff on Andres Serrano’s controversial artwork, “Piss Christ,” just to annoy any stray Christians who may have tuned in to the wrong channel. Nancy also receives a stern lecture about her nervous cross-border deportment from one of her Mexican bosses. “You think those guys who flew into the towers, that was their first time flying a plane?” he scolds her. “Practice!”

The Mexicans are impressed by Nancy’s Toyota Prius, however.

“Hybrid, eh?” one says, giving it and her an admiring look-over. (Nancy is wearing a pretty sundress, along with her aw-shucks smile.)

“Yeah, hybrid car,” she confesses. “Got to save those fossil fuels. Dead Iraqi children.”

It’s like a haiku, a product placement, and a political commercial all in one. But then, the fourth season of “Weeds” is taking place in an election year, something Ms. Kohan has told Entertainment Weekly she is keenly aware of. In an interview included in Showtime’s press package, she has also disclosed that the new season of “Weeds” has a theme. Can you guess what it is?

“I think the theme for this season is change,” Ms. Kohan says.

Imagine that! Great artists are always unpredictable.

bbernhard@nysun.com