Xavier Dolan’s up-close look at a mother-son relationship has the intensity of a John Cassavetes film — it can be gut-wrenching to watch.

Mommy, directed and written by Xavier Dolan. At Kendall Square Cinema, Cambridge, MA.

A scene from “Mommy”

By Betsy Sherman

Xavier Dolan’s gale-force Mommy contemplates what it is to have a mother, what it is to be a mother, and what it is to feel like you’ve had enough of being a mother—although you know that you’ll always remain a mother. It can be gut-churning to watch, but it’s well worth it. Dolan’s up-close look at a mother-son relationship has the intensity of a John Cassavetes film; the one that first comes to mind is A Woman Under the Influence, with its free-flying emotions and its sense that abundant love isn’t always enough to overcome adversity.

In a quiet suburb in Quebec, the title character Diane “Die” Després (Anne Dorval) is captured in full explosive mode when she’s involved in a fender-bender. Interestingly, since within minutes we’ll be completely caught up in her life, our first look at her is from a protected distance, through the windshield of a random onlooker. Die wears what many would say is too much make-up and too-tight clothing for her 46 years. Her Québécois dialect is thick and abrasive (audiences in France get subtitles too). Her very bad day soon gets worse: the group home in which her delinquent 15-year-old son lives is kicking him out because he set a fire.

Die has had to scramble to provide for herself and her son Steve (Antoine-Olivier Pilon) since her husband’s death. Not having had much schooling, she relies on charm. This works best—in person, and in a low-cut top—with men, but she can smooth-talk women as well. The mother and child reunion is affectionate and boisterous, attracting the stares of neighbors. Their banter is laced with curses in both Canadian French and English, and there’s a hint of sexual tension. They vow to be a team and embark on the dubious venture of home schooling. But it’s soon clear that Steve doesn’t have the coping skills to live up to his part of the bargain. Die describes him as having ADHD, but there seems to be a more serious mental disability there. Steve has the tantrums of a child, with the strength of a man. In a sweet gesture, he presents Die with a (shoplifted) necklace that reads “Mommy.” Among the highs and lows that follow, this token remains on Die’s neck, catching the light in especially ironic moments.

One of those above-mentioned neighbors, Kyla (Suzanne Clément), a pixie-ish woman of around 40, looks on the surface as if she’ll shun the tacky Die. Instead, she comes to fill a need in the Després household, and Die and Steve fill a hole in her life. Kyla is a teacher, but a recent trauma has caused a rupture between her thoughts and her ability to speak them; she’s now on sabbatical. Kyla becomes Steve’s tutor as well as Die’s friend, and Die is free to take on a full-time job. Mommy’s triumvirate earns a place in the cinematic tradition of depicting damaged souls who have patience for each other’s flaws and gain strength from each other’s presence.

Dolan and his collaborators break with tradition, however, in the visual presentation of Mommy. We recently experienced some fun-with-aspect-ratio in The Grand Budapest Hotel, during which Wes Anderson switched to the nearly square vintage-film ratio of 1.33:1 for scenes set in the 1930s. His reasons had to do with whimsy and nostalgia. Dolan’s experimental use of the actual square of a 1:1 ratio has a more trenchant psychological effect. It produces not only a claustrophobic, but also a voyeuristic feel, as if we’re peeping at the drama through a crack in a doorway. There is some opening and reclosing of the view, with the clever instance of one character pushing the edges of the picture open, to the invigorating sound of Oasis’s “Wonderwall.”

It’s tempting to call Mommy an actress’s showcase, what with the powerful turn by Dolan as the gutsy Die and the poignant performance of Clément as Kyla. Then you realize that wow, Pilon just seems to be Steve, it doesn’t even feel like he’s acting. Dolan’s film gets under the skin, and stays there.

Betsy Sherman has written about movies, old and new, for The Boston Globe, The Boston Phoenix, and The Improper Bostonian, among others. She holds a degree in Archives Management from Simmons Graduate School of Library and Information Science. When she grows up, she wants to be Barbara Stanwyck.