The Age of Diagnosis

How the Overdiagnosis Epidemic is Making Us Sick

By: Suzanne O’Sullivan

Narrated by: Suzanne O’Sullivan

'She is in my view the best science writer around' SATHNAM SANGHERA

We live in an age of diagnosis. But have we gone too far?

We live in an age of diagnosis. The advance of sophisticated genetic sequencing techniques means that we may all soon be screened for potential abnormalities. The internet provides a vast array of information that helps us speculate about our symptoms. Conditions like ADHD and Autism are on the rapid rise, while other new categories like Long Covid are driven by patients themselves.

When we are suffering, it feels natural to seek a diagnosis. We want a clear label, understanding, and, of course, treatment. But is diagnosis an unqualified good thing? Could it sometimes even make us worse instead of better?

Through the moving stories of real people, neurologist Suzanne O'Sullivan explores the complex world of modern diagnosis, comparing the impact of a medical label to the pain of not knowing. With scientific authority and compassionate storytelling, she opens up new possibilities for how we might approach our health and our suffering.

©2025 Suzanne O’Sullivan (P)2025 Hodder & Stoughton Limited

Critic reviews

'Exceptional... Chapter by brilliant chapter, [The Age of Diagnosis] raises fundamental questions we should all be asking when thinking about illness, be it cancer or genetic disorders, never shying away from difficult truths.' (Hannah Barnes)

These are incredibly difficult areas to explore...O'Sullivan is brave to take this subject on, and she hits the target... O'Sullivan is an excellent, fluid writer, and an eloquent speaker... In a world where medical misinformation and disinformation flourish, and people die as a result, it takes courage to counter them without pandering to stereotypes. But that is what The Age of Diagnosis does so well... Its overall message is clear: diagnosis is a tool to be wielded with the utmost caution, and tolerance for difference and for imperfection can go a long way in keeping us healthy. (Adam Rutherford)

The Age of Diagnosis covers so many topics that have been troubling me but which I hadn't been able to resolve myself. It slices through the confusion and the contradictions that have tied me in knots - both as a parent and as a clinician - with grace, elegance and compassion. It is scholarly and human, but an absolutely absorbing read from start to finish. There are very few people who could write this so straightforwardly and yet with endless compassion. I really cannot say good enough things about it. (Chris van Tulleken, author of ULTRA-PROCESSED PEOPLE)

How does she carry off that high wire act, being so technical and expert and grounded in data, while telling stories in a way that makes them utterly addictive? I love the way she listens to people talking. It's a really important, intelligent, compassionate and brave book, and it speaks very eloquently to things happening in our ideas about ourselves. (Tessa Hadley)

A humane and thoughtful observer of the oddities of the human mind... full of intriguing case studies and wise observations. Her new book ranges widely, taking in the drawbacks of mass screening for illnesses as well as the perils of overextending mental health categories... We make people sicker by by the simple act of diagnosing them with a medical problem. A fascinating book. (Robbie Millen)

A brave and deeply compassionate book with a very important message. (Henry Marsh)

Highly recommended

Finally someone saying what I have thought for so long. All doctors should read/listen to this.