The word “ecstasy” comes from the Greek ekstasis - ek meaning “out” and stasis meaning something like “stand.” And in religious terms, ecstasy has always meant to stand outside yourself; to transcend both your sins and earthly ties to the world for spiritual epiphany. Interesting then that outside of religious definitions, ecstasy often refers to thoroughly embodied experiences; food, sex, drugs.

Rose Glass’ arresting debut Saint Maud features two women who live on the opposite ends of this spectrum. Once celebrated dancer Amanda (Jennifer Ehle) is now ravaged by cancer, left wheelchair and carer-dependent in a dingy seaside town. But she still revels in any bodily pleasures she can, smoking, drinking, and enjoying the company of louche friends and attractive sex workers.

Amanda needs to be saved – at least that’s the opinion of new private nurse Maud (Morfydd Clark), a young woman with a face and indeed character that’s alternately delicate and violently clenched. Maud is a socially reclusive, God-fearing outcast whose background is hinted at through a chilling, blood-soaked opening, and brief encounters with a former co-worker (Lily Knight), who calls her by a different name.

But Maud’s current concern is Amanda’s soul, and her fervent faith soon escalates into blistering, controlling obsession. Maud’s eye-wateringly vicious methods of corporal mortification, and increasingly desperate prayers create a creeping sense of dread. What exactly will Maud do in the name of God?

From the opening scenes, Glass twists sensory elements to create a sense of alienating disquiet, elevating the film’s exploration of mind and body, suffering and salvation. The town’s arcades are viewed by Maud as twisted carnival of debauchery, as neon lights glare and gulls screech overhead as men remove glass eyes and seek out sex; meanwhile the tense, pulsing score evokes Maud’s psyche; tightening to the point of breaking. Subtle CGI exaggerates Maud’s eyes and mouth when in the grip of religious fervour – is this ecstasy, possession or just a sign that Maud’s experience of her own self is slipping further from reality?

Though Saint Maud employs some well-worn tropes of religion-themed horror, her precise style, psychological exploration, and intense atmosphere make this an extremely promising debut. Let us pray Glass gets the recognition she deserves.

Written and directed by Rose Glass. Starring Morfydd Clark, Jennifer Ehle, Lily Frazer, Lily Knight, Marcus Hutton. 84 mins

• 4/5

• In cinemas December 4