By Michael Greenberg
Bloomsbury, £12.99

What purpose is there in madness?”, King David asked God. The same question lies at the heart of Hurry Down Sunshine, Michael Greenberg’s mesmerising account of the acute psychosis that suddenly engulfed his daughter, Sally, when she was 15 years old.

Within the space of a few days, she turned from normal teenager into crazed visionary, convinced she had been chosen to cure the suffering of humankind. Her father and stepmother listened to her ravings with helpless anguish, hoping she would calm down, but the mania got worse: “It is as if the real Sally has been kidnapped,” Greenberg writes, “and here in her place is a demon, like Solomon’s, who has appropriated her body.”

Sally is admitted to a psychiatric ward, heavily sedated and eventually diagnosed with bipolar disorder. One of her fellow inmates is a young Chasid, who pores over his Torah with “hollow intensity”. His family cling to the hope that he is not mad but, says the Chasid’s brother, “has achieved devaykah” (communion with God). “Tell your daughter to leave him alone.”

Greenberg, an American critic, screenwriter and TLS columnist, is an acute observer of human life in all its beauty and folly. His account of the weeks of Sally’s illness and her slow, partial recovery is both exquisitely written and unflinchingly honest. While his ex-wife, Robin, sees their daughter’s breakdown as “a necessary phase in Sally’s evolution, her journey towards a higher realm”, he prefers to seek explanations in neurochemical imbalance and genetics (his brother has been on Thorazine for schizophrenia for over 30 years).

But Greenberg also worries about the effects of his broken first marriage, worries he has failed as a parent and as a human being. In her manic phase, Sally pours forth puns, a cruel irony to a man with Greenberg’s command of language. Movingly, he quotes James Joyce, who said of his own mad daughter, Lucia: “Whatever spark of gift I possess has been transmitted to her and has kindled a fire in her brain.”

The need to make sense of a loved one’s mental illness is as pressing as it is doomed. Ultimately, as Greenberg shows, there is just the fact of it and the task of living with it. Two months after being kidnapped by madness, the real Sally returns. Her “wayward black eyes” soften, her voice has warmth again. For Greenberg, there is no purpose, simply profound gratitude for this “miracle of normalcy”.