Age of Diagnosis O’Sullivan Suzanne (2026)

From autism to allergies, ADHD to long Covid, more people than ever are being labelled with medical conditions. But can a diagnosis do more harm than good? The boundaries between sickness and health are being redrawn as mental health categories shift and expand, changing what we consider normal. Genetic tests can detect pathologies decades before symptoms appear, sometimes before a person is even born, while increased health screening draws more people into believing they are unwell. An accurate diagnosis can bring understanding and improved treatment, but many diagnoses are less definitive than they seem and can turn healthy people into patients. Drawing on real peoples stories, decades of clinical practice and the latest medical research, Dr Suzanne OSullivan challenges long-held assumptions and transforms the way we think about illness and health.