Diagnoses, normality and systemic pressure: Niels Bilenberg on the evolution of ADHD diagnostics

Interview with Professor Niels Bilenberg about diagnostic trends and systemic pressures

Main theme: Pills, proof and polarization

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Over the past two decades, the number of children diagnosed with ADHD in Denmark has risen sharply—without evidence of a corresponding increase in symptoms in the general population. In this interview, Professor Niels Bilenberg reflects on diagnostic trends, systemic pressures, and how psychiatry might find a more balanced approach to supporting children in difficulty.

From a rare disorder to a common diagnosis

Nicolai Uhrenholt: When you look back over the past 10–20 years, how would you describe the development in the understanding of ADHD in Denmark?

Niels Bildenberg: If you look back twenty years, the diagnosis was still classified in ICD-10 as a behavioral disorder-hyperkinetic disorder-rather than as a neurodevelopmental condition, as we see it today. Over that period, the number of ADHD diagnoses has almost doubled. Yet studies suggest that the prevalence of ADHD-related symptoms in the background population has not increased. This could mean that our diagnostic threshold has shifted: today, we are more likely to make the diagnosis on a somewhat thinner symptomatic foundation than we did fifteen or twenty years ago.

When more attention leads to more diagnoses

What do you see as the main reasons for this increase?

Part of it reflects greater awareness. Schools, parents, and others have become better at identifying children with difficulties. But there is also a systemic element: because access to educational and social support often depends on having a diagnosis, there is a pressure on the system-and on us as child psychiatrists-to provide one. In some cases, the diagnosis becomes the only way for a child to receive the help they need.

The diagnosis as an entry ticket to support

What are the consequences when help is almost exclusively tied to a formal diagnosis?

It creates a distorted logic. The law says that children in need of help should receive it; it does not say that a psychiatric diagnosis must be the entry point. We should return to interpreting need as sufficient grounds for support. Otherwise, ordinary distress risks being medicalized and channeled into psychiatry unnecessarily.

Where does normality end and disorder begin?

How do you distinguish between normal variation in children’s behavior and a psychiatric disorder?

We have to be careful not to pathologize normal differences. Psychiatry risks taking over parts of normal variation and labelling them as pathology, particularly within ADHD and autism. Diagnoses should be reserved for cases where there is true pathology and clear functional impairment.

Niels Bilenberg: "ICD-11 is a step forward, but classification alone is not enough."

A changing childhood

You also mention changes in childhood itself. How do these influence diagnostic patterns?

The digital environment has fundamentally altered children’s everyday lives. Screen-based activities take up a large proportion of their waking hours, and that affects how they train executive functions such as working memory, attention, and persistence. When children practice these abilities less, they may appear more inattentive or restless-even if this reflects changes in upbringing rather than illness.

Regional differences and private practice

There are notable regional differences in diagnostic rates and medication use. How do you interpret that?

Some regions and municipalities have different thresholds for diagnosis, and the extent of private sector involvement also varies. Private assessments are not always reported to national registers, which creates uncertainty about the true numbers. We therefore see more people receiving medication than are officially registered with a diagnosis.

When a childhood diagnosis becomes a burden

How can a diagnosis be helpful in childhood but later problematic?

In childhood, it can provide access to support in school. But later in life it can limit opportunities-for instance when applying for insurance or certain types of education or employment. We occasionally see young adults who wish to have their diagnosis removed because it restricts them. That shows that a diagnosis can be both a help and a hindrance.

How diagnoses are made in practice

How is the diagnostic process organized in child and adolescent psychiatry today?

It is a multidisciplinary process. Psychologists, nurses, and other professionals collect information, and the diagnosis is made at a case conference where a specialist in child psychiatry participates. Ideally, every child would be seen directly by a specialist, but workforce limitations make that impossible at present.

Towards clearer guidelines and better assessment tools

What should professional societies prioritize to achieve a more balanced and consistent practice?

We need clear clinical guidelines that genuinely assist clinicians, and more consensus about which diagnostic instruments to use. Most importantly, we lack good tools for assessing functional impairment. Symptom descriptions are well developed, but function is harder to measure. Better functional assessment instruments-including patient- and parent-reported outcomes-would help us make more precise and transparent diagnoses.

The promise and limits of ICD-11

Will ICD-11 improve the situation?

ICD-11 is a step forward, but classification alone is not enough. We also need accompanying clinical tools that translate criteria into practice. Only by combining clear diagnostic definitions with validated instruments for symptoms and function can we reach more reliable and comparable assessments.

Thank you for the conversation. □