The changing prevalence of ADHD? A systematic review

Abstract

Introduction: Understanding the prevalence of Attention Deficit Hyperactivity Disorder (ADHD) and changes in demand for related healthcare services is crucial for effective healthcare policy and resource allocation. Clinicians, teachers and charities have reported increasing demand for ADHD assessments in recent years, overwhelming support systems. This review synthesises post-2020 studies of ADHD prevalence and incidence.

Methods: We conducted systematic searches in Web of Science, Embase, Medline, Global Health, and PsycInfo using terms relating to ADHD and prevalence. Additional sources included public health databases, Google, and study reference lists. Studies were included if they contained original data relating to general population rates of ADHD and we extracted data relating to methods of assessment and measures of prevalence and incidence. We followed PRISMA and synthesis without meta-analysis (SWiM) guidelines.

Results: Forty studies across 17 countries, with one study spanning 42 countries, were reviewed. No significant rise in ADHD prevalence was found, although incidence was found to vary during the COVID-19 pandemic. Only four of the included studies were at low risk of bias.

Limitations: There are substantial limitations in the quality of the literature included in this review. Due to significant delays in reporting prevalence data, estimates from previous reviews may be inaccurate. There is a lack of healthcare data and no school-level data.

Conclusions: Significant research gaps exist in determining ADHD prevalence and incidence. The highest quality findings do not suggest an increase in prevalence since 2020 but indicate some variability in incidence during the COVID-19 pandemic. Further research is urgently needed to guide clinical practice and public health policy.

Keywords: Attention deficit hyperactivity disorder; COVID-19; Diagnosis; Healthcare resources; Incidence; Schools.