The Age of Diagnosis: Sickness, Health and Why Medicine Has Gone Too Far
Suzanne O’Sullivan, Hodder, £10.99

HOW can we have too much diagnosis? The claim seems especially weird coming from a highly qualified doctor. It’s a bit like a pub landlord denouncing the evils of the demon drink.

Certainly, there has been an explosion in the number of people diagnosed with illness. O’Sullivan puts forward a number of explanations: people’s expectations of medicine have risen dramatically, placing demands on doctors to diagnose; definitions of disease have also expanded to cover conditions that would previously have been considered “ordinary life experiences” like “bodily imperfections, sadness and social anxiety”; and finally, breakthroughs in technology, screening and genetics can detect earlier and milder forms of disease. The result is “diagnosis creep.”

Is this a bad thing? O’Sullivan’s answer is “not necessarily.” The key test is whether a diagnosis leads to demonstrably better outcomes. All too often this is not the case and “the ability to diagnose outstrips ability to cure, meaning people are living with a diagnosis for longer, but not necessarily [living] longer as a result.”

To prove her point she digs deep into a range of case studies. These include Huntington’s and Lyme disease, autism, long Covid, genetic cancer screening, ADHD, depression, neurodiversity, and finally the “syndrome without a name.” Yes, such a thing exists. To O’Sullivan’s credit, she is scrupulously fair throughout, reports different points of view, and allows patients to speak for themselves. The result is both fascinating and at times surprising.

Take long Covid. Did you know that this condition was patient-created, and the first disease to arise from a thread on Twitter (now X)? Or that there are now an eye-watering 200 symptoms under the heading long Covid that range from classic post-viral problems like fatigue, to things like “loneliness,” “feeling scared” and “skin ageing”?

By March 2023 a staggering 1.9 million people had self-assessed with the disorder. Yet despite numerous studies across the world there is no proven relationship between the severity of a Covid infection and the likelihood of developing long Covid. The disease apparently “contradicts biology.” For example: “Sufferers who are most short of breath also have the most normal lung function tests.” In short, most symptoms are “best explained by a psychosomatic illness.”

It’s important to note that O’Sullivan does not therefore dismiss the damage caused by long Covid or any of the other conditions she covers. Post-viral infections are real, and so were the consequences of the government’s Covid policies. As a result anxiety, depression and loneliness caused by the lockdowns are “a better predictor of who would develop long Covid than a positive test for the virus.”

Across the range of her case studies a pattern soon forms. Bearing in mind that many of the conditions diagnosed are effectively untreatable, the damaging effects of “diagnosis creep” can often outweigh any possible benefit. She argues this is particularly the case for mental health conditions that now cover a vast array of symptoms. There are now officially nearly 300 possible autism symptoms. As mental health conditions like autism spectrum disorder, ADHD and others become “catch-all,” inevitably more and more are diagnosed. While many patients are relieved, this risks “robbing people of control over their own futures and distracting from the need for social change.”

Overdiagnosis can also damage physical health. We all know about the “placebo effect.” Similarly, medical labels have the power to make us sick. This, the so-called “nocebo” effect creates an expectation of sickness “that actually generates symptoms when there is little or no disease.” The issue is particularly controversial because of the rise in predictive and high-tech cancer and genetic diagnosis.

Cancer screening has many benefits, but there is no evidence it reduces overall mortality. It also cannot distinguish between a slow-growing cancer and the ones that cause health problems. But all are treated equally aggressively. So, there is a real danger people who don’t need treatment receive invasive procedures and suffer severe health effects. As she puts it: “For every life improved by screening, just as many, if not more, may be made worse. For every life saved, another may be lost.”

O’Sullivan has produced that rare thing: a book that forces the reader to question common sense. The only major weakness is her relative neglect of social, economic and political factors. While she does show how private doctors, screening firms and big tech corporations are profiteering, a more political approach is needed. If she is correct, then Labour’s love affair with private medicine and technology will inevitably lead to perverse outcomes.

In that sense, overdiagnosis is ultimately another morbid symptom of capitalist crisis.