Pay attention to the title of the movie Saint Maud. Really think about what it is that makes someone a saint. In fact, if you look up some of the key saints from Christianity you’ll find the path to sainthood is often paved in blood. Be it through obscure instances of violence or culpable sin, the title of saint is still considered as an undertaking of absolute faith with the good grace of God standing as its ultimate reward.

Rose Glass’ Saint Maud looks at all this through a different lens, employing psychological horror to produce one of the most disturbing explorations of faith, devotion, and mental illness in recent memory.

Written and directed by Glass, Saint Maud follows a young, pious nurse called Maud as she comes to terms with the meaning of her relationship with God. In essence, Maud lives to answer the question of what God wants with her. As she looks for answers, she’s assigned to take care of a woman dying of cancer. Maud believes she can save the troubled woman’s soul, but God seems to have a harder test in the works for her.

The movie’s most resounding successes rest on the shoulders of actress Morfydd Clark, who plays Maud. Clark masterfully captures the title character’s tug and pull with being both hopeful and lost at the same time. Clark plays Maud as a young woman constantly teetering between a full-blown mental breakdown or a divine revelation.

Maud is given brief but revealing bits of internal dialogue that keeps viewers informed on the latest developments on what she thinks God is asking of her. Morfydd’s narration does a great job of showing Maud’s frustrations with her lack of understanding, always aware of the mounting pressure she faces while trying to make sense of her situation.

Saint Maud plays a bit with what’s real and what’s inside the main character’s head, but it prefers the less ambiguous approach to what’s actually happening. There’s more evidence of Maud suffering from a severe mental illness rather than a fundamental crisis of faith. And yet, it’s her faith that wins out as the thing that guides her in this new phase of life as a recent convert. Maud wasn’t always religious. There’s an obscure trauma at play that the movie cleverly keeps pretty much under wraps. It’s what might explain how God has so completely taken a hold over her.

The manifestations of her faith do one very unique thing here that not many other horror movies can claim to do. It makes the movie unfold as a kind of possession story where God is the invading spirit. Maud’s religious devotion plays a central role here as her decision to give in to faith keeps her isolated from almost everyone else.

Glass’ script is careful not to overindulge with the supernatural elements, but whenever something gives the appearance of being otherworldly, the horror gets ramped up considerably. Glass does an excellent job of playing with shadows and dark corners without stripping a single scene of all color. In fact, the movie contains a very clear and solid color palette that serves to heighten the terror at the heart of Maud’s process.

This figures into Glass’ decision to put Maud in big open spaces that aren’t exactly crowded with people. Quite the opposite. Maud seems to live in a world devoid of meaningful human contact. This becomes an especially powerful source of pain while in the presence of male characters, none of which see Maud as someone worth being treated with care or respect. Maud’s world is hostile and even God is suspect.

Saint Maud has a lot of moving parts, each made more complex and disturbing thanks to the fact the element of faith serves as its source of horror. Clark’s performance elevates the story’s focus on the consequences of unchecked piousness with an eye to question not just religious behavior but also the effects it can have on a troubled mind. As far as explorations into these matters are concerned, Saint Maud stands as one of its greatest.