Article Text

Influence of the month of birth on persistence of ADHD in prospective studies: protocol for an individual patient data meta-analysis
  1. Corentin J Gosling1,2,
  2. Charlotte Pinabiaux1,
  3. Serge Caparos3,4,
  4. Richard Delorme5,6,
  5. Samuele Cortese7,8,9,10,11
  1. 1Department of Psychology, DysCo Lab, Paris-Nanterre University, Nanterre, France
  2. 2Department of Psychology, EA 4057, Université de Paris, Paris, France
  3. 3Department of Psychology, DysCo Lab, Paris 8 University, Saint-Denis, France
  4. 4Institut Universitaire de France, Paris, France
  5. 5Department of Child and Adolescent Psychiatry, Assistance Publique - Hopitaux de Paris, Paris, France
  6. 6Human Genetics and Cognitive Functions, Institut Pasteur, Paris, France
  7. 7Center for Innovation in Mental Health, School of Psychology, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
  8. 8Clinical and Experimental Sciences (CNS and Psychiatry), Faculty of Medicine, University of Southampton, Southampton, UK
  9. 9Solent NHS Trust, Southampton, UK
  10. 10Hassenfeld Children’s Hospital at NYU Langone, New York University Child Study Center, New York City, New York, USA
  11. 11Division of Psychiatry and Applied Psychology, School of Medicine, University of Nottingham, Nottingham, UK
  1. Correspondence to Dr Corentin J Gosling; corentin.gosling{at}


Introduction Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder with symptoms, especially the hyperactive ones, that tend to decrease in severity with age. Interestingly, children born just before the school-entry cut-off date (ie, the youngest pupils of a classroom) are at higher risk of being diagnosed with ADHD compared with children born just after the cut-off date. Noteworthy, this month-of-birth effect tends to disappear with increasing absolute age. Therefore, it is possible that young children erroneously diagnosed with ADHD due to their month of birth present a lower chance to have their diagnosis confirmed at a later age, artificially reinforcing the low persistence of ADHD across the lifespan. This protocol outlines an individual patient data (IPD) meta-analysis of prospective observational studies to explore the role of the month of birth in the low persistence of ADHD across the lifespan.

Methods and analysis Five databases will be systematically searched in order to find prospective observational studies where the presence of ADHD is assessed both at baseline and at a follow-up of at least 4 years. We will use a two-stage IPD meta-analytic approach to estimate the role of the month of birth in the persistence of ADHD. Various sensitivity analyses will be performed to assess the robustness of the results.

Ethics and dissemination No additional data will be collected and no de-identified raw data will be used. Ethics approval is thus not required for the present study. Results of this IPD meta-analysis will be submitted for publication in a peer-reviewed journal.

PROSPERO registration number CRD42020212650

  • ADHD
  • persistence
  • month of birth
  • meta-analysis

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  • Twitter @CorteseSamuele

  • Contributors CJG, CP, SCa, RD and SCo have designed research. CJG, CP, SCa, RD and SCo have either written or edited the manuscript.

  • 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 SCo declares honoraria and reimbursement for travel and accommodation expenses for lectures from the following non-profit associations: Association for Child and Adolescent Central Health (ACAMH), Canadian ADHD Alliance Resource (CADDRA), British Association of Pharmacology (BAP), and from Healthcare Convention for educational activity on ADHD. All other authors have no conflict of interest to declare.

  • Patient consent for publication Not required.

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

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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