A father's unswerving love for his drug-addicted 18-year-old pride and joy is tested to the limit of endurance in Belgian director Felix van Groeningen's sensitively handled drama.

Based on two emotionally raw memoirs - Beautiful Boy by David Sheff and Tweak by his son Nic - the handsomely crafted film is a sobering account of one family's battle of attrition with a demon that sinks its jaws into a prodigal child and refuses to let go.

There are no huge emotional crescendos in a chronologically fragmented narrative assembled by van Groeningen and co-writer Luke Davies.

Instead, we are silent and tearful witnesses to moments of compassion, aching regret and anguished surrender that leave us in no doubt of the devastation wrought by drugs on the user and everyone in his chaotic orbit.

Beautiful Boy is anchored by commanding performances from Steve Carell as the patriarch, who staunchly refuses to admit defeat even when it is causing pain to other members of his family, and Timothee Chalamet as the teenager with a trembling finger on the self-destruct button.

When we meet David Sheff (Carell), he is a senior writer for prestigious magazines including Rolling Stone, Vanity Fair and Wired, who famously conducted the last major interview with John Lennon and Yoko Ono in 1980 for the cover of Playboy.

His first wife Vicki (Amy Ryan) lives in Los Angeles, amicably sharing custody of their son Nic (Chalamet), while David builds a new life in San Francisco with his partner Karen (Maura Tierney) and their children Jasper (Christian Convery) Daisy (Oakley Bull).

David suspects Nic is in the grip of addiction and he persuades his boy to attend Ohlhoff Recovery Centre.

"I'm doing it for you," snaps Nic.

Treatment appears to go well until the teenager goes AWOL during free time.

"Relapse is a part of recovery," explains the centre's director (Amy Aquino).

"That's like saying crashing is part of pilot training," responds David, who applies his journalistic mind to learning everything about drugs and their treatment.

Punctuated by flashbacks to Nic's youth to underscore the unbreakable bond between father and son, Beautiful Boy is anchored by powerhouse performances from the two leads.

Considering the depth of David's feelings for his child - "I love you more than everything," he whispers at an airport departure gate - it is curious that the film observes each small victory or setback with a cool detachment that mutes our emotional response.

That said, few images in van Groeningen's picture linger quite like the sight of Chalamet, Oscar nominated as Call Me By Your Name's lovesick adolescent, injecting methamphetamine on the filthy floor of a public restroom and collapsing among the detritus like a discarded rag doll as poison courses through his twitching limbs.

A high and a devastating low, perfectly framed.