“What’s in your head?” Dolores O’Riordan’s raw, plaintive refrain loops through the Cranberries’ 1994 hit Zombie. A protest song about the Troubles could, on paper, hardly seem further removed from Derek Owusu’s third novel, about a young writer recovering from a mental health crisis. But in an author’s note before The Recovery House begins, Owusu instructs the reader to listen to the song “at least two to four times before going beyond this page”. Gradually it becomes clear that the song’s central question is one Owusu’s protagonist asks in various forms throughout the novel.

Can we ever fully understand what is going on in our own heads? We meet Jamal, a young novelist who has woken up in a recovery house – a residential alternative to hospital admission – after a breakdown. It transpires that he has overdosed, is an alcoholic, and has been diagnosed with borderline personality disorder. He is in a frazzled, frantic state, initially less interested in getting better than in piecing together how he got there.

The house itself is hardly a sanctuary in the conventional sense: Jamal finds a single bed with protruding springs, dead cockroaches in the nightstand and restless corridors in which people in various states of distress move around one another. Jamal’s nurses watch him; he watches them back. Owusu knows the world he is writing about – he spent a summer in a recovery house himself after a mental health crisis, and there is an intimacy to the way he renders this suspended, in-between place.

Writing is both Jamal’s vocation and his illness. Like Owusu, he has published two books and won an award for his first; the expectations surrounding the third have become unbearable, and he eventually remembers that it was the attempt to write it that precipitated his breakdown. He comes to the frightening realisation that “the thing that inspired me is the thing that’s trying to kill me”. His frustration with the world of publishing is also evident: “why does everyone in this industry want something from you even though we’re all very aware that things usually take time.”

A woman staying in the room below Jamal sings Zombie’s chorus in the night, over and over, until he finds himself singing it too, flooding his mind in interstitial moments. The singer, Joy, eventually slips a pen and paper beneath his door, something the nurses have refused him for fear of what writing will provoke. From there, they develop a tender, almost soulmate-like friendship, which becomes inflected with religion when the pair begin a weekly Bible study session together. Faith, as rendered by Owusu, is not cruel or exacting. There is something almost prelapsarian in Jamal and Joy’s relationship with God, as there is about their friendship – an innocent, platonic love. Between them, “What’s in your head?” transforms from a fear into an invitation: tell me.

The recovery house gradually becomes a strange, fragile ecosystem for Jamal’s convalescence. He shares cigarettes with its motley crew of residents, observes their dramas and begins to emerge from himself. It offers something a hospital cannot: a temporary, disparate community of people who understand that we are perhaps all closer to the precipice of collapse than we like to imagine. “Who was well in the world anyway?” one of the patients asks, concluding: “there was only the sick and those who didn’t realise it yet”.

At just 160 pages, The Recovery House is a very small book about some very large questions: what separates illness from inspiration? When does that inspiration become compulsion, when does self-examination slip into self-destruction? Owusu is interested in the porous boundaries between these states, and his prose mimics them. Written in long, free-flowing sentences, with sparse punctuation and no conventional chapter markings, the novel has the rhythm of a poem, one thought spilling into the next before it can be contained.

Owusu’s novel is slight enough to cradle in your hands, and it feels as though it must be handled in this way: with care, liable to shatter if held too tightly. It is a uniquely honest and affecting meditation on art, religion and mental health, told with a preternatural tenderness. At times it is almost painfully raw, reading like an excavation of the soul of a writer wondering whether, in turning his life into art, he has also been exploiting it.