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Addiction, whether to alcohol or drugs, has been the subject of many films, some of them of extraordinary quality. “Beautiful Boy,” based on the complementary memoirs by David Sheff and his son Nic, whom he tried to rescue from his destructive habit, doesn’t quite match the best, but it has some remarkable elements—not least a performance by Timothée Chalamet that confirms what “Call Me By Your Name” signaled, that he’s one of the most magnetic and committed young actors working today.

But Felix von Groeningen’s film, which he co-wrote as well as directed, is not quite worthy of Chalamet’s talent. It’s an earnest but only sporadically moving portrait of a boy who slips into a spiral of drug abuse and of the father who tries desperately, but ineffectually, to pull him back from the brink.

Part of the problem is that the younger actor so easily outshines his co-star Steve Carell, who plays David, a freelance writer. He and Nic (played successively by Kue Lawrence, Zachary Rifkin, Jack Dylan Grazer and Chalamet), live in San Francisco with David’s second wife Karen (Maura Tierney) and their two kids Jasper (Christian Convery) and Daisy (played first by Carlee Maciel and then Oakley Bull). Nic’s mother Vicki (Amy Ryan) lives in Los Angeles, and she and David have kept up a relatively amicable relationship, with Nic visiting her for holidays.

Nic appears from all accounts to be a sweet, well-adjusted kid, but appearances are deceiving. He’s been experimenting with drugs of all kinds, getting addicted to crystal meth, and rather than going off to college, he enters a detox residential clinic. When he graduates to a halfway house, however, he goes AWOL, and David charges off to find him among the city’s dark byways.

That sets the pattern of what follows through the rest of the film. Nic has periods of recovery—at one point he does, in fact, go off to college—but his urge to shoot up never goes away; at one point on a visit home that seems to be carefree, he steals money from his adoring younger brother to feed his craving, prompting an argument with David that leads to him stalking off and sinking ever deeper into addiction. He takes up with a girl named Lauren (Kaitlyn Dever) who’s a junkie too, and they’ll eventually break into David’s house to rob the place.

Chalamet brings genuine pathos to Nic’s seemingly relentless cycle of temporary respite and recurrent failure, bringing an engaging directness to the periods of sobriety and a sense of danger that can explode into venomous anger during his relapses. It’s another nuanced, affecting performance from an actor of signal accomplishment and extraordinary promise, even if Van Groenjngen chooses to hold back at some points, hesitating to depict the full extent of the depths to which Nic succumbs.

The plot, in any event, is really more David’s than Nic’s. He has to overcome the belief that if he only handles things the right away and gives his son the proper kind of encouragement and support, he can bring the boy back from the hell he’s sinking ever deeper into. He agonizes over his repeated failures, which poison his relationship with Vicki, who holds him responsible for Nic’s self-destructive behavior. She takes her son in at one point, but is no more successful than her ex-husband had been; and it’s only after David has come to the hard realization that he can’t save Nic, and must withhold any support from the boy, however much he might plead or demand or whatever empty promises of reform he might make—even if doing so puts his son in danger of overdosing.

Carell works diligently to get all of this across in his performance, and to an extent his effort pays off. But there’s a sense of strain and stiffness throughout that contrasts with Tierney, who gracefully conveys Karen’s pain at witnessing her husband’s tendency to privilege the needs of his older son over those of his youngster children. The tykes who play Jasper and Daisy at their various ages give nicely natural performances as well, as does Andre Royo as Nic’s long-suffering AA sponsor, while Dever does a solid job as Lauren. But it was probably a mistake to cast Timothy Hutton in a cameo as a therapist David consults about his son’s addiction; an unknown would have been less intrusive at that point.

The film is well produced, with straightforward lensing by cinematographer Ruben Impens, and good work from production designer Ethan Tobman and costumer Emma Potter. It’s not the fault of editor Nico Leunen that the narrative takes on a certain repetitiveness; that’s the nature of the story rhythms.

“Beautiful Boy” tells a sadly familiar story, and does so with dignity and economy, if not with the final measure of truthfulness. But its only really outstanding element is another remarkable performance from Timothée Chalamet; it might well bring him another Oscar nomination.