Methylphenidate for Children and Adolescents with ADHD – unpublished trials

Introduction This is a follow-up study on a recent systematic review by Storebø et al. [[1][1]]. It aims to investigate research waste and publication bias in randomized clinical studies investigating the use of methylphenidate for children and adolescent with ADHD. Method The method used includes an initial cohort selection from searching [Clinicaltrials.gov][2] and the EUCTR with the following inclusion criteria: Use of methylphenidate either as stand-alone or part of psychological treatment for ADHD, randomised clinical trials, any dosage, any delivery method and at least 75% children and adolescents with ages less than 18. Results The primary objective is to assess how many randomised clinical trials of methylphenidate on children and adolescents with ADHD are registered in protocol databases, but never published in academic literature or as tabular summary results. The number of participants included in these trials is a secondary objective. The tertiary objective is to assess the time from registry to publication of randomised clinical trials of methylphenidate on children and adolescents with ADHD in either a journal or as summary results, and the number of participants in these trials. The cutoff time for a publication to be considered timely published will be 12 months, as per FDAA guidelines [[3][3]] ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: ClinicalTrials.gov and the EUCTR database I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced are available online at [clinicaltrails.gov][4] and the EU clinical trials register [1]: #ref-1 [2]: http://Clinicaltrials.gov [3]: #ref-3 [4]: http://clinicaltrails.gov