Overdiagnosis: A Growing Concern in Modern Medicine
Suzanne O’Sullivan, a seasoned neurologist with 25 years of experience, raises a critical point about the rising trend of overdiagnosis in today’s medical landscape. In her thought-provoking new book, The Age of Diagnosis, she delves into the intricate relationship between sickness, health, and the notion that medical practices may have strayed too far into the realm of excessive labeling.
O’Sullivan’s exploration spans a wide range of conditions, including ADHD, autism, chronic Lyme disease, hypermobile EDS, and PoTS. Her primary concern is not that individuals are becoming less resilient; rather, she argues that, despite the best intentions, the proliferation of medical diagnoses can be detrimental to our well-being. Overdiagnosis occurs when individuals are classified as patients based on issues that, if unrecognized, would likely cause them no real harm. This mindset, often embraced as a “better safe than sorry” approach, can inadvertently pathologize normal variations in life.
This phenomenon may explain the sudden and widespread recognition of conditions like ADHD and autism, as well as the increasing reliance on preventive screenings for illnesses such as dementia and cancer. Recent statistics underscore this trend: UK adult ADHD diagnoses have surged twentyfold; a 2021 study revealed a staggering 787% increase in autism diagnoses from 1998 to 2018; and in 2024, NHS cancer diagnoses climbed by 5%.
Notably, while the overall number of diagnoses has risen dramatically, the most severe cases of ADHD and autism—those that significantly impair daily functioning—have remained relatively stable.
Why Are We Overdiagnosing?
O’Sullivan identifies several driving factors behind this alarming trend. “First of all, we had an underdiagnosis issue for a long time,” she explains. Historically, genuine suffering often went unrecognized or was diagnosed too late. “We’re eager to rectify that, but I believe we’ve overcorrected, operating under the assumption that more diagnoses equate to better outcomes.”
Commercial interests also play a significant role; ADHD prescriptions have risen by 18% annually since the onset of the pandemic. However, O’Sullivan contends that the motivations of scientists contribute as well. “When we develop a new MRI scan, there’s a strong desire to utilize it widely. When quick genetic tests become available, there’s an inclination to identify who else may benefit.”
Another aspect to consider is human nature. “People crave answers. Doctors, eager to satisfy their patients, will often provide them, especially when the scientific culture supports such actions.” O’Sullivan describes this as a “collusion between society, scientists, and healthcare professionals.”
This dynamic is particularly evident in the dramatic rise in diagnoses of neurodevelopmental disorders. “Autism used to affect one in 2,500 children; now, in Northern Ireland, it’s one in 20. One must question what is happening,” she asserts.
The Surge in Autism and ADHD Diagnoses
One of the central issues contributing to this rise is the phenomenon known as “diagnostic creep,” where the criteria for diagnosis shift from specific symptoms to encompass increasingly mild variations of those symptoms. “Some argue that mild autism was historically overlooked, and I acknowledge that. However, in our efforts to correct this, we’ve diluted the criteria to the point that we’re applying labels to individuals whose symptoms are so subtle they might go unnoticed.”
While she does not dispute the validity of individuals’ experiences, she questions whether those at the milder end of the spectrum genuinely benefit from a diagnosis. Given the dramatic increase in diagnoses over the past three decades, one would expect to see tangible improvements, yet the evidence does not support that assertion. Advocates within neurodivergent communities argue that the world is not structured to accommodate their needs, but O’Sullivan believes this perspective overlooks existing progress. “I’m not suggesting the world is ideal, but despite various accommodations, we have not observed measurable improvements,” she states.
She references a Canadian study comparing ADHD-affected children who received accommodations with those who did not; while the former reported feeling supported, objective measures revealed no real improvement in outcomes.
Beyond neurodevelopmental conditions, O’Sullivan highlights the issue of overdiagnosis in other areas. In her book, she examines long Covid as a case study of how diagnoses can go awry from their inception.
Long Covid: A Diagnosis Born from Social Media
Typically, a diagnosis is anchored in a specific condition, with a range of symptoms evolving around that core. However, long Covid emerged from a hashtag and gained traction faster than thorough research could be conducted. O’Sullivan notes, “In a matter of months, people believed they understood what long Covid entailed, despite the lack of comprehensive studies.”
She posits that long Covid patients likely belong to distinct categories: those suffering from post-viral syndrome, those facing organ damage due to hospitalization, and those experiencing an entirely different set of symptoms. “During the pandemic, with many avoiding medical consultations, it became inevitable that this period would serve as a breeding ground for psychosomatic conditions.”
Throughout her book and interviews, O’Sullivan emphasizes that the quest for diagnosis reflects authentic pain deserving of support. However, she warns that labeling can impose limitations on individuals. For children, autism and ADHD diagnoses might hinder their development. “My aim is not to undermine the suffering experienced by individuals. Instead, I want to question whether medicalizing these experiences is the most effective management strategy,” she clarifies.
In her view, society currently regards an ADHD or autism diagnosis as the best solution for a struggling child. She advocates recognizing the child’s suffering and finding ways to offer support without resorting to medical diagnoses. This perspective is especially relevant for those on the mild end of the spectrum who can cope but still encounter challenges.
“Currently, the definition of impairment is so vague that it creates significant difficulties, despite the stark contrast between someone who perceives their differences as manageable and someone who is non-verbal and requires constant assistance,” she explains.
The Impact of Diagnosis on Mental Health
For conditions characterized by heightened bodily awareness, such as long Covid, a diagnosis can exacerbate symptoms. Increased focus on the body leads individuals to notice irregularities they might otherwise overlook, creating a cycle where the brain anticipates and maintains symptoms.
This scenario illustrates a psychosomatic condition—an authentic, debilitating ailment without a biological basis. “When I state that long Covid has psychosomatic components, I’m not dismissing the suffering involved. Some of the most severely affected patients I encounter suffer from psychosomatic illnesses. The challenge lies in the persistent stigma surrounding these conditions. By addressing these theories, I advocate for a more respectful and serious approach to these issues.”
Because psychosomatic illnesses are rooted in mental rather than physical causes, traditional medical treatments may inadvertently worsen symptoms. They require nuanced therapeutic approaches to address effectively.
Determining the Value of a Diagnosis
So, how can we discern whether ADHD or autism diagnoses are beneficial or harmful? Many individuals find validation and relief through diagnosis—doesn’t that hold intrinsic value? “I completely understand that many people experience a sense of validation and relief upon receiving a diagnosis,” O’Sullivan states. “However, once that moment of validation passes, what comes next? Has the diagnosis genuinely provided long-term benefits? I remain unconvinced that the initial validation sustains itself over time.”
She expresses particular concern for children still forming their identities. “The drawback of a diagnosis is that once you label yourself as neurodevelopmentally atypical, it can feel like you possess an insurmountable challenge. Rather than maturing out of it or striving to overcome it, attention shifts to perceived limitations.”
O’Sullivan believes a diagnosis can also shape how teachers and society perceive these children, potentially setting unhelpful expectations. She observes this pattern in her work with epilepsy patients. Previously, individuals with dissociative seizures—psychological rather than neurological in nature—were often overlooked until their symptoms escalated into seizures. Nowadays, many young patients arrive with extensive lists of diagnoses. “I’ve encountered dissociative seizure patients since my early training. What’s striking is the increase in patients arriving with numerous medical labels in their early twenties.”
In contrast to the past, where she suspects patients experienced various symptoms before developing seizures, today’s patients often accumulate diagnoses for each symptom. “I now see individuals in their twenties burdened with long lists of symptoms and medical labels. It’s not merely that they didn’t receive diagnoses two decades ago—they likely didn’t even exhibit those symptoms back then. Through the medical system and support groups, they are directed into a particular narrative, resulting in an accumulation of symptoms that were previously unseen and unclassified.”
Diagnosis: An Artistic Endeavor
O’Sullivan acknowledges that her views may be contentious. “Almost everything I’ve discussed will provoke some reaction. However, these conversations are essential.” She advocates for rigorous scientific evaluation to assess how diagnoses impact health outcomes. “No one has genuinely investigated whether the increase in diagnoses correlates with improved health results.”
On an individual level, she urges caution against rushing into diagnoses or viewing them as absolute truths. “Diagnosis inherently involves a degree of subjectivity, even with advanced technological tools. Medicine is an art, and the most crucial aspect is listening to the patient’s story, rather than solely relying on tests.”
“If a diagnosis does not come with a treatment aimed at recovery but instead relegates you to the role of a patient fixating on symptoms, perhaps it is something you could forgo. It’s vital for individuals to understand that these uncertainties exist, enabling them to evaluate whether the labels they adopt genuinely assist them or inadvertently hinder their progress.”
The Age of Diagnosis by Suzanne O’Sullivan is published by Hodder (£22).
