Binnie Kirshenbaum is both a writer’s writer and a New Yorker’s New Yorker. Her debut novel, “On Mermaid Avenue” (1992), a sort of anti-coming-of-age story set in Coney Island, already evinces the raucous, caustic comedy and bred-in-the-bone commitment to the boroughs that have since become her hallmarks. Over seven subsequent novels and a short-story collection, her vision has only become bolder and darker. Her women are creatures of intellect and appetite, fiercely observant and self-aware. They like sex and cigarettes, prefer cats to children; most are working artists. Lila Moscowitz, the narrator of “Pure Poetry” (2000), writes X-rated formalist verse in a haunted Greenwich Village apartment. Bunny, the protagonist of “Rabbits for Food” (2019), is a depressive novelist whose violent outburst at a New Year’s Eve dinner lands her in a psych ward, where she’s forced to do creative-writing exercises as part of her art therapy.

“Counting Backwards” by Binnie Kirshenbaum. Soho, 392 pages. $28

Kirshenbaum’s new novel, “Counting Backwards,” centers on a pair of middle-aged, middle-class Manhattanites: Addie, a collage artist, and her husband, Leo, a research scientist. The novel — like “Rabbits for Food” — is written in short chapters with sarcastic titles. Many chapters fit on a single page with white space to spare. But where “Rabbits” is narrated in an unobtrusive third person (save for Bunny’s writing exercises, which appear at intervals throughout the text), “Counting Backwards” is told in the second person, a relatively rare mode for literary fiction that cannot help but call attention to itself:

“Your social circle is wide: artists, academics, scientists, people who work in publishing or with nonprofit organizations, and a handful of architects thrown into the mix. To define people by their professions is insultingly reductive, as if how they earn a living were their totality, which it’s not, but you all do it anyway.”

I admit that I initially found the second person a dubious choice, but I was quickly won over. When a writer chooses to use “you” in a piece of fiction, it’s typically a pretext for direct address (“I’m telling you this story”) or else a surrogate “I” that attempts to put the reader into the world of the story (as in “choose your own adventure”). Kirshenbaum’s “you,” which follows Addie’s point of view, feels less like either of these than like the quasi-dissociative, self-hectoring “you” that the mind slips into during an emergency or while watching a good friend’s bad play: “You have to get through this,” “You know it will be over soon,” etc.

This “you” is less intimate than claustrophobic, underscoring the isolation and loneliness that set in as the couple’s world contracts after Leo starts having visual and auditory hallucinations. He looks out the window of their apartment and sees Gandhi standing on the sidewalk. He hears Siberian huskies howling in the next room. There are lapses in memory and motor skill. Addie tracks her husband’s symptoms in a notebook, terse jottings that are the logical extension of the novel’s tendency toward brevity. Here is a chapter called “Holiday Surprises,” in full:

“No jewelry for me

“Calls sister to ask, Did you know Dad died? (Father died 12 yrs ago)

“Wants to rewrap gifts already opened

“Asks if I want to go to Times Sq. to watch the ball drop*

“*Stark raving mad question.”

Leo is suffering from Lewy body dementia, a particularly cruel brain disorder that is eroding his ability to care for himself as well as his relationship to reality. The disease’s causes are uncertain, as is the pace of its progress. Addie is told that the decline might last anywhere from three to 20 years — a harrowing prospect both for Leo, whose intellect is central to his sense of self, and for Addie, who is already struggling to bear the emotional and financial disaster their little family is facing.

Addie puts Leo into a care facility, then another, but the conditions are execrable, the cost exorbitant, and she still needs to hire a private caregiver to tend to him. She ends up renting a second apartment near her own for Leo and his health aide, Larissa, to live in. This also makes it easier to visit every day, though that prospect, too, grows painful, as Larissa and Leo fall into a domesticity that leaves Addie feeling like an interloper.

Larissa is a finely drawn character: a capable caregiver, genuinely tender toward Leo and sensitive to Addie’s anguish — but not the stereotypical self-effacing saint we might have expected (with a sigh) to see rolled out for pathos. Larissa refuses the offer of vacation days, not out of duty to her ward but because she would prefer their equivalent as a lump-sum payout at the end of the year. When spending Addie’s money on food or home decor, she tends to splurge. However intimate the work she does, Larissa never loses sight of the fact that she is a worker, and Addie a boss: She doesn’t let Addie lose sight of it, either.

Compounding the horror of Leo’s illness is the constant humiliation and stress of figuring out how to pay for the care he now requires. Addie borrows money from her sister-in-law and tries to sell more of her artwork, but her slide into debt is inexorable:

“Other than to run errands and visit Leo, it’s like you’re under house arrest. All streaming services, magazine subscriptions, and Leo’s phone service have been canceled. You’ve got enough art supplies to last you twelve decades. That leaves the maintenance on your apartment, Con Ed, Wi-Fi, your phone, minimum payments on the credit card bill, and food, litter, and toys for Roberta and Howie. You can deprive yourself, but how do you explain to cats why you have no treats to give them?”

Though this is far and away Kirshenbaum’s bleakest book — which is saying something — she has not lost her knack for narrative propulsion or her ear for pitch-black comedy. Neither has she wobbled in her conviction that the lives of jaded, childless, cosmopolitan elites have as much inherent value as anyone else’s. (Granted, we’re hardly the identity group in most acute need of defense these days, but it was still nice to hear someone say.) I know it’s only March, but I’m calling it early: “Counting Backwards” is the feel-bad novel of the year.

Justin Taylor is the author, most recently, of the novel “Reboot.”