Ah, to de-glam. It’s one of the surest shortcuts to newfound artistic appreciation: a bedraggled deviation into dowdy drama by a beautiful star. Acclaim by way of sweatpants.

‘CAKE’ Rated: R Opens Friday

"Cake," in which Jennifer Aniston plays a bitterly grieving, caustically acerbic and chronically pained Los Angeles woman, belongs to a contrived kind of low-budget movie — drab and depressed, but predictably poignant — just as artificial as any blockbuster convention.

As Claire Simmons, Aniston has facial scars, stringy hair and a slightly frumpier frame. But this is also a very recognizable Aniston, whose deserved appeal has always depended on marrying her pert all-American girl-next-door with a glib sarcasm. In "Cake," she has turned up her cynicism knob as far as it will go.

She lives largely holed up in her handsomely designed suburban L.A. home, popping pills, struggling with sleeplessness and haunted by appearances of a friend (Anna Kendrick) from her self-help group who committed suicide by leaping from a highway overpass. "Way to go, Nina!" Claire announces to the group, prompting its leader (Felicity Huffman) to show her the door.

Claire’s Mexican housekeeper Silvana (an exceptional Adriana Barraza) cooks food she won’t eat and shuttles her around town, usually in the pursuit of more pills.

Claire lies reclined in the passenger seat, laid flat by back pain from the vaguely referenced car crash that left her scarred. Whatever the particulars, the accident’s trauma is eventually clear enough: Claire lost her son in it.

She crankily putters around, lashing out at most, lonely from the absence of her husband (Chris Messina), who, like everyone else, tired of her hostile moping. All but Silvana have deserted her.

The audience is tested, too. "Cake," directed by Daniel Barnz from a screenplay by Patrick Tobin, is in many ways less about Claire’s threshold for pain than our tolerance for hers. In one telling scene with her fed-up physical therapist (Mamie Gummer), Claire confronts her, insisting that her pain isn’t an act, it’s real. The therapist responds with a question: Do you want to get better, really?

The film very slowly builds to the always-expected catharsis. Barnz hides all images of Claire’s son until one late, crushing jolt of pathos, a decision that could be said to be manipulative. But the blankness to Claire’s history also reflects the point of the film: We don’t see the wounds people are carrying around, even in the broad daylight of the California sun. Would we have stuck it out with Claire?

But by never fleshing out Claire’s life, "Cake" never expands beyond a wallowing in pain, which starts to feel more and more like a concept rather than a deep emotion.

"Cake" is fine enough, though neither as funny nor as powerful as it thinks it is. Yet it’s a failure of today’s movies that the only pathway to "serious" recognition for an actress like Aniston is by suffocating her buoyant charm. She’s a sly comedic performer with a keen sense of timing and an inherent likability that a decade of perpetual tabloid obsession has failed to smother.

So where are the smart, witty romantic comedies she deserves? Instead, Aniston has been left to strip in "We’re the Millers" and play the sexy dominatrix of two "Horrible Bosses" movies. No wonder she’s so bent out of shape in "Cake."

Jake Coyle, Associated Press