In Jia Tolentino’s essay collection Trick Mirror, the writer recalls her childhood in Houston, Texas, where she attended superchurch services each weekend. There was a jumbotron, a pipe organ with over ten thousand pipes and 20,000 people singing loudly in unison.

There was a meaningful sense of both abandon and connection. It wasn’t until years later when Tolentino went clubbing and tried MDMA that she felt a similar sensation – ecstasy.

“I have always found religion and drugs appealing for similar reasons,” she writes. “(You require absolution, complete abandonment, I wrote, praying to God my junior year.) Both provide a path toward transcendence – a way of accessing an extrahuman worlds of rapture and pardon that, in both cases, is as real as it feels. The word ‘ecstasy’ contains this etymologically, coming from the Greek ekstasis – ek meaning ‘out’ and stasis meaning ‘stand’. To be in ecstasy is to stand outside yourself.”

Of course standing outside yourself isn’t always a form of ecstasy, and complete abandonment isn’t always a form of rapturous connection. To stand outside yourself can also be a form of survival, disassociation and dysfunction.

In The Outrun, Saoirse Ronan plays Rona, who we meet when she’s living in London. She's joyously losing herself to the neon haze and thumping beats on club dancefloors, and it’s in one of these nightclub settings where she encounters Daynin (Paapa Essiedu), who becomes her longterm boyfriend. Rona doesn’t know the line between losing herself and abandoning herself, drinking to the point of belligerence, blackouts and obliteration. We see her start fights, hit people and fall into a canal.  Drinking - the very activity which allowed her to connect with others - has now become the very thing that pushes everyone around her away.

The Outrun explores Rona’s relationship with loneliness beautifully. Based on Amy Liptrot’s critically acclaimed memoir, we experience Rona’s relationship with alcohol and landscape non-chronologically, with the story jumping from her self-destructive wild days in London, a long stint in rehab and a return to her home on the isolated Orkney islands off the northeast coast of Scotland. It's here where she spends time with her separated parents, religious convert Annie (Saskia Reeves) and bipolar father Andrew (Stephen Dillane) - whose swings from warm and passionate to cold and depressive offer a parallel to Rona’s own struggles and an insight into the unpredictable nature of what connection looked like to her growing up.

Each chapter is marked by a bone-deep sense of loneliness. An early scene in Orkney sees Rona ask a man for a cigarette in an effort to strike up a conversation, her sadness and desire for friends emanating from every pore. In rehab, she observes her peers’ engagement with animal therapy but doesn’t participate, and when another recovering addict shares his hopes for the future, Rona looks blank, stating simply, “I cannot be happy sober.” Post-rehab she moves to an isolated part of the islands, retreating from the locals’ offers of kindness, often donning headphones which blare thumping techno - muting the sounds of those around her as well as the wild landscape.

The scarred female psyche is something that German director Nora Fingscheidt has explored before, in System Crasher, the story of a traumatised girl with anger issues, and The Unforgivable, which starred Sandra Bullock as an ex-con trying to find her place in the world.

The Outrun is Fingscheidt's most formally inventive work. Not only do the non-linear structure and use of hardcore music against a sweeping natural backdrops create a sense of fragmentation; she also brings in the intellectual threads from Liptrot’s memoir, which go into folklore, history and nature facts about the Northern Isles, including tales of selkies (mythological mermaids), maritime history and bird migration paths. These threads include the use of animation, archival footage, and photographs, with a voiceover belying the film’s literary origins.

What works well on the page often proves to have uneven results onscreen. The chronological jumps are effective in revealing the extent of Rona’s self-destruction, but when combined with the intellectual threads they interrupt and dilute the sense of immersive connection to the landscape that’s vital to the film’s emotional core. The shots of Orkney’s wild, windswept cliffs and crashing waves are impressive, and may add to an intellectual understanding of the landscape, but the fragmented structure and diversions hinder emotional connection to it.

These issues lie in the direction, not Ronan’s performance, which is the most mature of her career. Her portrayal of Rona’s aggression, desperation, self-judgement and sadness are beautifully, painfully authentic, layered with a deep understanding of the character’s history and the self-destructive cycle she finds herself trapped in. The moments where Ronan begins to show us Rona’s connection to the landscape and her slow healing are often interrupted, disrupting the emotional progression and saturation of the piece, as well as the pacing itself.

The most impactful scenes are when Fingscheidt lets the camera linger with Ronan as she finds moments of connection. Whether she's forging a gentle fireside connection with someone, slowly submerging herself in sea water, or, as in the final scene, ecstatically conducting ocean waves. In these moments we feel Rona finally stop abandoning herself. Instead she stands resolute, the life-affirming possibility of connection emanating from the screen.  It may not be ecstasy, but it’s self-acceptance.

• The Outrun is in cinemas from September now. Watch the trailer below.