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Twenty years of research on attention-deficit/hyperactivity disorder (ADHD): looking back, looking forward
  1. Samuele Cortese1,2,3,4,5,
  2. David Coghill6,7,8
  1. 1 Academic Unit of Psychology, Center for Innovation in Mental Health, University of Southampton, Southampton, UK
  2. 2 Clinical and Experimental Sciences (CNS and Psychiatry), Faculty of Medicine, University of Southampton, Southampton, UK
  3. 3 Solent NHS Trust, Southampton, UK
  4. 4 New York University Child Study Center, New York City, New York, USA
  5. 5 Division of Psychiatry and Applied Psychology, School of Medicine, University of Nottingham, Nottingham, UK
  6. 6 Departments of Paediatrics and Psychiatry, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia
  7. 7 Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
  8. 8 Royal Children’s Hospital, Melbourne, Victoria, Australia
  1. Correspondence to Dr Samuele Cortese, Academic Unit of Psychology and Clinical and Experimental Sciences (CNS and Psychiatry), University of Southampton, Southampton SO17 1BJ, UK; samuele.cortese{at}


In this clinical review we summarise what in our view have been some the most important advances in the past two decades, in terms of diagnostic definition, epidemiology, genetics and environmental causes, neuroimaging/cognition and treatment of attention-deficit/hyperactivity disorder (ADHD), including: (1) the most recent changes to the diagnostic criteria in the Diagnostic and Statistical Manual of Mental Disorders and International Classification of Diseases; (2) meta-analytic evidence showing that, after accounting for diagnostic methods, the rates of ADHD are fairly consistent across Western countries; (3) the recent finding of the first genome-wide significant risk loci for ADHD; (4) the paradigm shift in the pathophysiological conceptualisation of ADHD from alterations in individual brain regions to a complex dysfunction in brain networks; (5) evidence supporting the short-term efficacy of ADHD pharmacological treatments, with a different profile of efficacy and tolerability in children/adolescents versus adults; (6) a series of meta-analyses showing that, while non-pharmacological treatment may not be effective to target ADHD core symptoms, some of them effectively address ADHD-related impairments (such as oppositional behaviours for parent training and working memory deficits for cognitive training). We also discuss key priorities for future research in each of these areas of investigation. Overall, while many research questions have been answered, many others need to be addressed. Strengthening multidisciplinary collaborations, relying on large data sets in the spirit of Open Science and supporting research in less advantaged countries will be key to face the challenges ahead.

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  • Contributors SC drafted the paper. DC revised the first draft.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests SC declares reimbursement for travel and accommodation expenses from the Association for Child and Adolescent Central Health (ACAMH) in relation to lectures delivered for ACAMH, and from Healthcare Convention for educational activity on ADHD. DC declares grants and personal fees from Shire and Servier; personal fees from Eli Lilly, Novartis and Oxford University Press; and grants from Vifor.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.