Nuanced and moving: Julia Roberts and Lucas Hedges in Ben is Back.

hours, and in its brief span shows up the other recent kid-on-drugs film Beautiful Boy. From the first frame it’s clear that this reserved and low-key picture is not so shamelessly portentous, not so eager to wrench our heartstrings without earning the right to. There’s no Neil Young on this soundtrack.

The film’s trick is authenticity, much of it provided by Roberts. Like any mother, Holly’s thrilled to see her son home, even as her husband and daughter eye him warily. But fear of a relapse lingers: she smothers Ben in hugs, then promptly hides all the medication and jewellery in the house.

Indeed, aside from one obligatory scene at a 12 Steps meeting and a brief conversation with a jittery tweaker, this is an addiction drama with barely a needle or broken lightbulb in sight. It explores the corrosive impact of drugs through the consequences it wreaks on families and communities. The pall of Ben’s past life hangs over the story. Rather than rely on tedious flashbacks or grating explanation – as Beautiful Boy did to its detriment – director Peter Hedges (Lucas’ father) cleverly contrives to have Ben revisit places from his wigged-out days, forcing him to contend with selfish blindness. We get the traumatised afterglow, rather than weightless re-enactment.

Which is not to say that Ben is Back is a mirthless and dire experience. In places where you least expect them, someone will crack a dark and cynical joke, such as when Holly brutally excoriates the now-senile family doctor for giving Ben powerful painkillers when he was a teenager, setting in motion a cycle of habit.

It’s a moment that is shocking, funny and pathetic all at once.

Of course, Holly’s outburst (among others) is just another expression of that fierce protection. And as the film spirals towards a tough conclusion, it’s through Roberts’ extraordinary, haunting performance that we see how devotion truly has no limit.

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She smothers Ben in hugs, then promptly hides all the medication and jewellery in the house.