Invited Keynote: Prof Arnstein Mykletun, PhD (Norway)

There is a 10-fold variation in ADHD diagnosis rates among patients referred to Norwegian child and adolescent mental health services (CAMHS), despite no corresponding variation in ADHD symptoms across catchment areas. This reflects the ADHD controversy within CAMHS: clinicians with a liberal approach believe diagnoses enable access to beneficial treatments, while restrictive clinicians are concerned about medicalisation, stigma, and side-effects. This controversy creates quasi-random variation in the likelihood of receiving a diagnosis, driven by clinician provider preferences rather than patient need.

Using Norwegian registry data for all patients aged 5–17 (n>35,000) referred to 73 CAMHS in 2009–2011, we followed participants for 10 years on high school dropout and disability benefit awards. Diagnosis rates varied considerably between CAMHS despite no variation in ADHD symptom load in catchment populations. We identified an instrumental variable based on clinicians’ diagnostic preferences along the liberal-to-restrictive spectrum to estimate the causal effect of receiving an ADHD diagnosis. A liberal approach to diagnosing ADHD causally increased both school dropout and disability pension awards over 10 years of follow-up, even after adjustment for individual and catchment area characteristics. While a liberal diagnostic approach enables more patients to access medication and psychosocial interventions, the diagnosis likely also reshapes self-identity and expectations during formative years. Iatrogenic social and psychological effects of the diagnostic label may outweigh treatment benefits — particularly given that patients commonly discontinue medication over time. This study suggests the marked rise in ADHD diagnoses over recent decades may, on balance, be more harmful than helpful for patients at the margin of diagnosis.

 

  

Learning objectives:  Delegates will be able to:

1. Understand ADHD as a dimensional construct rather than a true clinical dichotomy, and to appreciate how the threshold for diagnosis is shaped by clinician attitudes and provider preferences rather than patient symptom load alone.

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2. Critically evaluate the evidence on long-term outcomes of ADHD medication, and to understand why medication may not deliver the beneficial outcomes commonly assumed in clinical practice.

 

3. Consider the possibility that receiving an ADHD diagnosis may, for patients at the margin, be more harmful than helpful — through iatrogenic effects on self-identity, expectations, and life trajectories. And to reflect on the population-level consequences of clinical decision-making in ADHD.

  

Level: All levels. It will be of interest to neuropsychologists at all career stages, from those new to ADHD assessment through to experienced clinicians and researchers engaged in the broader diagnostic and policy debate.

 

Presenter: Prof Arnstein Mykletun, PhD (Norway)

Arnstein Mykletun is Head of the Centre for Population Health, Haukeland University Hospital, Bergen, Norway, and Professor of Community Medicine at UiT – The Arctic University of Norway. He holds a European Certificate in Psychology (EuroPsy) and is a licensed clinical psychologist with experience in cognitive behavioural therapy. Prof Mykletun also holds appointments as Honorary Visiting Professor at the Institute of Psychiatry, King’s College London, and at Monash University, Melbourne, as well as Senior Researcher at the Norwegian Institute of Public Health and Head of Research at the Centre for Work and Mental Health, Nordland Hospital Trust. Prof Mykletun’s research spans psychiatric epidemiology, occupational mental health, public health, and health services research, with a focus on the population-level consequences of clinical decision-making and the use of causal inference methods, particularly instrumental variable designs. He holds an H-index of 89 with over 31,500 citations and is currently PI for grants exceeding approximately AUD 15 million. Prof Mykeltun has been elected Chairperson of the Section for Epidemiology and Social Psychiatry of the European Psychiatric Association, and was named Academic of the Year in Norway in 2024. Prof Mykletun is the principal investigator of the ADHD Controversy Project, a large-scale natural experiment using Norwegian population registry data to examine the long-term consequences of ADHD diagnosis and medication. He also leads a parallel Controversies in Psychiatry project on compulsory mental health care. Prof Mykletun chaired a Norwegian Government expert committee on sickness absence whose recommendations became national policy, and has contributed to WHO expert consultations on the inclusion of ADHD medication on the List of Essential Medicines.

  

Keywords: ADHD; population effects of clinical decision-making; causal inference