ADHD “Overdiagnosis”: What Does the Evidence Actually Show?

Recently the question of whether ADHD is being overdiagnosed has become a frequent topic in the media. Coverage in the general public often suggests that ADHD diagnoses are increasing rapidly and implies that clinicians may be medicalising normal variations in attention or behaviour.

An often overlooked consequence of the “overdiagnosis” narrative is the impact it can have on people who are trying to make sense of lifelong difficulties. Many adults who seek assessment describe years of struggling with attention, organisation, emotional regulation or overwhelm without understanding why these challenges felt so persistent or disproportionate. For some, the possibility of ADHD offers a framework that helps these experiences make sense. When public discourse suggests that ADHD is being widely overmedicalised, it can reinforce stigma and self-doubt. In clinic, it is not uncommon to meet individuals who feel hesitant or even guilty about pursuing assessment, worrying that they are somehow seeking a label for difficulties that should simply be endured. This hesitation can delay help-seeking further, particularly for groups whose ADHD has historically been under-recognised, such as women and adults presenting later in life

A recent editorial in the British Journal of Psychiatry takes a clearheaded look at this public discourse and asks the question: what does the evidence actually show?

The authors, who include the most respected academics researching neurodevelopmental conditions in the UK, argue that the widely repeated claim that ADHD is being overdiagnosed in the UK is not supported by strong evidence. Instead, the picture that emerges from epidemiological research and clinical practice is more complex and in many ways points towards the opposite problem.

Prevalence and recognition

Estimates of ADHD prevalence have been relatively consistent across studies for many years. Research suggests that ADHD affects around 5% of children and approximately 2–3% of adults.

When these figures are compared with the number of people who actually receive a diagnosis and appropriate treatment, a gap becomes apparent. Many individuals with ADHD remain unrecognised or unsupported, particularly in adulthood.

This discrepancy suggests that the issue may not be widespread overdiagnosis, but rather historical under-recognition combined with increasing awareness.

Why the “overdiagnosis” narrative persists

Several factors may contribute to the perception that ADHD is suddenly being diagnosed too frequently.

First, awareness of ADHD in adults has increased significantly. Many adults who struggled for years without an explanation are now seeking assessment. This can create the impression of a sudden surge in cases, when in reality it may represent previously unrecognised conditions coming to light.

Second, access to assessment has expanded outside traditional NHS pathways. Private assessments and independent services have increased in response to long NHS waiting lists. For some observers, this shift has raised concerns about diagnostic standards.

The BJPsych editorial makes the hugely important point that the quality of assessment matters a great deal. Where comprehensive diagnostic processes are followed, including taking a careful developmental history and consideration of alternative explanations, the risk of inappropriate diagnosis is substantially reduced.

The debate should therefore focus not on the existence of ADHD itself, but on ensuring robust and responsible assessment practices.

ADHD and diagnostic complexity

Diagnosing ADHD in adults is not always straightforward. Symptoms often overlap with other conditions, including anxiety disorders, depression, trauma-related difficulties and sleep disorders.

In addition, ADHD frequently co-occurs with other neurodevelopmental conditions such as autism.

This complexity means that good assessment requires time, clinical experience and careful exploration of lifelong patterns. Screening questionnaires alone cannot provide a diagnosis; they must be interpreted within a broader psychiatric evaluation but a clinician with expertise in ADHD but also the range of psychiatric conditions which frequently co-occur.

When this process is followed properly, the aim is not simply to confirm ADHD but to understand the whole clinical picture.

The risk of missed diagnosis

While concerns about overdiagnosis dominate public discussion, many clinicians remain equally concerned about missed diagnosis.

This is particularly relevant for groups who have historically been overlooked in ADHD research and clinical pathways, including:

• women and girls

• adults presenting later in life

• people with co-occurring mental health conditions

• individuals from minoritised backgrounds

  
  

Women, for example, may present with internalised symptoms such as emotional dysregulation, overwhelm or chronic exhaustion rather than overt hyperactivity. These patterns are sometimes interpreted as anxiety or mood disorders without considering the possibility of underlying ADHD.

Similarly, adults may develop compensatory strategies that mask difficulties until life demands increase or support systems change.

In these situations, the challenge is not excessive diagnosis but recognising patterns that have been present for many years.

Why the quality of assessment matters

The debate about overdiagnosis highlights an important principle: diagnostic labels should be applied carefully and responsibly.

A thorough ADHD assessment should typically include:

• a detailed developmental history

• exploration of symptoms across the lifespan

• structured diagnostic interviews

• assessment of functional impact

• screening for co-occurring conditions

• consideration of alternative explanations for symptoms

  
  

This level of assessment allows clinicians to differentiate ADHD from other conditions and to identify where symptoms may reflect overlapping or interacting difficulties.

Moving beyond polarised debates

Public discussions about ADHD often become polarised between two extremes: claims that the condition is dramatically overdiagnosed, and arguments that it remains widely under-recognised.

The reality is more nuanced.

ADHD is a well-established neurodevelopmental condition with clear evidence supporting its existence and clinical impact. At the same time, the increasing number of people seeking assessment highlights gaps in service provision and the need for careful diagnostic practice.

Rather than focusing solely on whether ADHD is over- or underdiagnosed, a more productive question may be: how can we ensure that people who need assessment receive accurate and thoughtful evaluation?

A focus on careful clinical practice

The BJPsych editorial provides a useful reminder that debates about diagnosis should remain grounded in evidence and clinical reasoning.

For clinicians, this means continuing to prioritise:

• comprehensive assessments

• careful differential diagnosis

• awareness of diverse presentations of ADHD

• collaboration with patients to understand lifelong patterns of difficulty and strength

  
  

When assessment is conducted thoughtfully, diagnosis can provide clarity and open the door to effective support.

For many adults, understanding ADHD is not about applying a label for its own sake. It is about making sense of longstanding experiences and identifying strategies and treatments that allow them to move forward more effectively.