In 2013, self-taught Swedish filmmaker David F Sandberg entered a short film competition with a creepy horror starring his wife, Lotta Lotsen, as a woman plagued by a strange entity who only appears when she turns out the light. While the original short didn't win first prize, it went viral and caught the eye of producer Lawrence Grey who recommended it to James Wan, who then helped Sandberg direct a feature written with Eric Heisserer (who penned the remakes of The Thing and A Nightmare on Elm Street).

In a similar style to Jennifer Kent's The Babadook, Heisserer turns the monster into a metaphor for mental health issues. Sophie (Maria Bello, talking to herself and portraying trembling fear with conviction) has been suffering all her life from the depression that has cost her two husbands and seen her two children, Rebecca (Teresa Palmer) and Martin (Gabriel Bateman) become scared of her.

Lots of time is spent shading in the relationship between protective older step-sister Rebecca, who has long since fled the roost, and Martin who is living a waking nightmare with an unhinged mother. These family issues culminate in a terrifying sleepover that delivers a claustrophobic face-off in a darkened basement; grisly killings and visceral encounters that all end with a swift bang.

Sandberg's ability to craft chilling jump scares bodes well for future projects. He nimbly draws out grippingly tense sequences in badly lit locations and the use of practical effects is wonderful. The sound design, especially an eerie scratching noise used in a sinister, rouge hued set-piece is particularly unsettling. It's just a shame, however, that the conclusion is so bleak and ill-judged.

Wide release from Fri 19 Aug.