The Age of Diagnosis

An ambitious book about modern diagnosis from the neurologist and prize-winning author of It's All In Your Head.

The boundaries between sickness and health are being redrawn.

Mental health categories are shifting and expanding all the time, radically altering what we consider to be 'normal'.

Genetic tests can now detect pathologies decades before people experience symptoms, and sometimes before they're even born.

And increased health screening draws more and more people into believing they are unwell.

An accurate diagnosis can bring greater understanding and of course improved treatment. But many diagnoses aren't as definitive as we think. And in some cases they risk turning healthy people into patients.

Drawing on the stories of real people, as well as decades of clinical practice and the latest medical research, Dr Suzanne O'Sullivan overturns long held assumptions and reframes how we think about illness and health.

Review

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 brave and deeply compassionate book with a very important message. -- Henry Marsh

In my view the best science writer around - a true descendant of Oliver Sacks. -- Sathnam Sanghera

A book of great wisdom as well as compassion - the result of decades working along the frontiers of brain, mind and body. Modern medicine is powerful; with care and with stories from her clinic, Dr O'Sullivan shows just how harmful it can be too. -- Gavin Francis, author of ADVENTURES IN HUMAN BEING

I loved this beautifully written and provocative book. The Age of Diagnosis asks brave and important questions, taking on the medical establishment as well as contemporary societal norms. O'Sullivan's primary motivation in her writing, her philosophy and her work as a doctor is extreme empathy and advocacy for her patients. -- Christie Watson, author of THE LANGUAGE OF KINDNESS

O'Sullivan explodes conventional wisdom about medical diagnoses. She knows that having a diagnosis like austism, or ADHD, or depression, or Lyme disease, can give her patients relief at having an explanation. But she also invites us to wonder where these diagnoses came from. Are we overdiagnosing? Is this really the best strategy for helping people get better? With clarity of prose and reasoning, The Age of Diagnosis should make all of us think about whether we are more or less healthy when we receive a diagnostic label. -- Elizabeth F. Loftus, Distinguished Professor, University of California, Irvine

The neurologist Suzanne O'Sullivan has written insightful books about psychosomatic conditions. Here she turns her attention to the perils of over-diagnosis - including autism, allergies, ADHD and long Covid. Be prepared for compassionate and bracingly independent thinking. ― The Times books to look out for in 2025

About the Author

Dr Suzanne O'Sullivan has been a consultant in neurology since 2004, first working at The Royal London Hospital and now as a consultant in clinical neurophysiology and neurology at The National Hospital for Neurology and Neurosurgery, and for a specialist unit based at the Epilepsy Society. She specialises in the investigation of complex epilepsy and also has an active interest in psychogenic disorders. Suzanne's first book It's All in Your Head, won both the Wellcome Book Prize and the Royal Society of Biology Book Prize and The Sleeping Beauties was shortlisted for the Royal Society Science Book Prize. She is from Dublin, Ireland.