Insomnia

Insomnia by Sarah Pinborough is a standalone psychological thriller published in April 2022, named one of the best thrillers of the year and adapted for a Paramount+ series. Following the success of Behind Her Eyes, it returns Pinborough to the claustrophobic domestic territory she does best - but grounds it in something more immediately recognisable than the supernatural: the fear of becoming your mother.

Emma Averell has spent most of her adult life running from her past. She has a high-powered career as a divorce attorney, a stay-at-home husband, two children, and a beautiful home. She has also told everyone she knows - including her husband Robert - that her mother is dead. The truth is harder to manage: at forty, Emma's mother suffered a catastrophic mental breakdown, was institutionalised, and has never left. Emma is the same age now that her mother was then. Twelve days before her own fortieth birthday, she wakes at 1:13 a.m. and cannot get back to sleep.

What begins as ordinary insomnia deteriorates quickly. Emma starts losing chunks of time she cannot account for. Compulsive behaviours begin surfacing - checking the locks, counting numbers, reciting fragments of a half-remembered rhyme - that mirror exactly what her mother did before she was taken away. Her estranged sister Phoebe reappears without warning for the first time in years, right as everything starts unravelling. And a mother Emma told Robert was dead turns out to have been accused of murder.

Pinborough builds the Unreliable Narrator tension here with particular skill: Emma is a lawyer, trained to assess evidence and dismantle unreliable accounts, and watching that professional clarity fail her under sleep deprivation is genuinely unsettling. The central question - is Emma's deterioration the result of inherited mental illness, her own unresolved Trauma and Healing, or something being done to her - is held in genuine suspension across the novel's length rather than resolved prematurely. Every character in Emma's orbit is shadowed with suspicion as a result: does Robert resent the career Emma has while he manages the house? Is Phoebe's reappearance at this precise moment a coincidence? The Gaslighting the novel explores sits somewhere between the external and the internal, which is what makes it so effectively disorienting.

The Family Legacy at the heart of the book - whether madness is inherited, whether the same fate is always waiting for the second-born daughter, whether what happened to Emma's mother must necessarily happen to her - gives the novel real thematic weight alongside its thriller mechanics. The Memory Loss that accumulates as Emma's sleeplessness deepens functions both as psychological terror and as plot device, since she genuinely cannot verify what she has or hasn't done during the gaps.

The Twist Ending has divided readers in Pinborough's familiar fashion, with the final stretch of Mystery and Secrets Revealed proving the book's most debated element: some find it a satisfying, clever payoff to everything carefully built before it; others feel the resolution strains against the realistic register the rest of the novel has established. For readers who came to Pinborough through Behind Her Eyes and found the supernatural element divisive, this one's resolution is grounded in reality - though Pinborough adds one layer that plays with that expectation in a way longtime readers will recognise as characteristic.