David Cronenberg’s screenplays give the overwhelming impression of intelligent dialogue between interesting people with driving obsessions, and their smarts let them keep a practical, analytical distance from the perverse things that fascinate them.

The Canadian director’s last film, 2022’s “Crimes of the Future,” made a meal out of the playful academic jousting in which Viggo Mortensen and Léa Seydoux engaged when they weren’t performing surgery on one another. But while that movie dealt with abstract concerns and lived in its own bio-futurist bubble, Cronenberg’s new movie “The Shrouds” is about something real: the death of his wife of 43 years in 2017.

Vincent Cassel plays a businessman named Karsh with a shock of frosty white hair a lot like Cronenberg’s own. The director says the resemblance is coincidental, but the way the recent loss of Karsh’s wife Becca (Diane Kruger) mirrors that of Cronenberg’s is most certainly not. “The Shrouds” is candid about what cancer does to the body in ways more conventional Oscar weepers rarely match.

Alternating between cool candor and anguish in his dialogue, slipping in and out of pained dream scenes, Karsh remains stubbornly devoted to his wife’s memory and invents an icky technology to keep her company from the other side of the grave. The details of this technology tilt the film toward body horror, a term first coined to describe Cronenberg’s work, but “The Shrouds” plays more like an indie drama than anything else.

Intrigue develops as shadowy geopolitical forces compete to get their hands on Karsh’s inventions. The details of the conspiracy are transcendentally irrelevant, and characters have a habit of seeming to explain the whole thing to the suspicious and foxy-eyed Karsh, who usually doesn’t believe a word of it.

Viewers weaned on tidier and more linear movies might take issue with how much conspiratorial clutter Cronenberg tacks onto the human plot, but he succeeds in creating a sense of general unease about foreign intervention and mass surveillance in a world connected to the internet. This is a defining movie about mourning, but it’ll also go down as a document of the distinct brand of paranoia that’s developed as this beleaguered century straggles to the quarter mark.

Besides, like the convoluted plots of so many noir films and spy thrillers, the conspiracy functions chiefly as a clothesline on which Cronenberg can hang the film’s emotional concerns. Some of these are rarely examined in film — Karsh’s sexual jealousy of the doctor operating on his wife, for instance, or the ruthless realism with which we see Becca’s body deteriorate.

There are other curious undercurrents. There is a vague unwholesomeness about dogs. A running joke involves the way Karsh’s morbid interests excite women. There’s the matter of Karsh’s Jewishness, emphasized in slow pans over the headstone where he hopes to one day join his wife in death, as well as in a dinner scene that celebrates Canada’s bounty of great kosher delicatessens.

The biggest surprise is how funny the movie is — laugh-out-loud funny, not just the kind where you smile to yourself because you get it. Despite the arch sheen, the movie isn’t afraid to exploit comedic chestnuts about fetishes, miscalculated dates and people who say the wrong thing at the wrong time. Some of the plot twists are so cockamamie they’re humorous in themselves, especially toward the end.

Movie snobs like to get prissy about people laughing at inappropriate times in theaters, but the correct response to “The Shrouds” is to laugh and then quickly have the laughter sucked out of your lungs as Cronenberg follows the rabbit holes of Karsh’s grief to deeper and more disturbing places. This is dark, dark comedy, but comedy nonetheless.

At 82, Cronenberg is in something like the full flower of his style. “Crimes of the Future” felt like a breakthrough even this deep into his career, combining the stately pace of dramas like “A Dangerous Method” and “Cosmopolis” with the biopunk nastiness of “The Fly” and “eXistenZ.” “The Shrouds” uses the same style in service of something much more real — too real for some, undoubtedly, but it’s some of the most essential and vital cinema of the year.