The prevalence of attention deficit hyperactivity disorder in Iran: An updated systematic review

Background: Attention deficit hyperactivity disorder (ADHD) is among the most common neurodevelopmental disorders in children and adolescents. There is a controversy over the true prevalence of ADHD in Iran, the knowledge of which is crucial for allocating health care resources and identifying research priorities. This is an updated systematic review of the prevalence of ADHD in Iranian children and adolescents.    Methods: For this systematic review, PubMed/Medline, Web of Science, Scopus, PsycINFO, IranPsych, IranMedex, Irandoc, Google Scholar, and grey literature were reached for publications between January 1990 and December 2018 that reported prevalence estimates of ADHD in Iran. Parallel independent assessments were conducted. The Quality Assessment Checklist for Prevalence Studies was used to assess the overall quality of studies. Results: A total of 34 original studies covering 33 621 Iranian children, adolescents, and adults were included. The included studies were mostly conducted on the population of preschool, elementary, middle, and high school-aged children as well as adolescents. Also, 6 studies addressed university students. Prevalence estimates of ADHD reported varied substantially across the studies and offered a range of heterogeneous data.    Conclusion: Overall, making exact comparisons among studies was not easy because the assessment method and the type of sampling could impact prevalence estimates. These factors need to be considered when comparing data from different studies.