Objectives: The purpose of this study was to assess the global incidence of attention-deficit and hyperactivity disorder (ADHD) among children.

Materials and methods: In this descriptive epidemiological study, age-specific rates (ASRs) incidence for ADHD in children (0-14 years) were presented (per 100000). The socio-development level was quantified by Socio-demographic Index (SDI), as a composite measure which includes income per capita, educational level for individuals aged 15 years and older, and total fertility rate for women younger than 25 years of age. Joinpoint regression analysis was applied to calculate the average annual percent change with 95% confidence interval (CI) to evaluate trends in 1990-2019.

Results: Global ASR of ADHD incidence in males was nearly three times higher than in females (307.9 per 100000 and 114.4 per 100000, respectively) in 2019. In both sexes together, the highest ADHD incidence was observed in high-SDI countries. Significantly decreasing trends for global ADHD incidence were observed both in males (by -0.4% per year, 95%CI=-0.4 to -0.3) and females (by -0.4% per year, 95%CI=-0.5 to -0.3). Trend of ADHD incidence in both sexes together decreased significantly (AAPC=-0.2; 95%CI=-0.3 to -0.1) in middle-SDI countries only.

Conclusion: The ADHD remains one of the most common neurodevelopmental disorders in children, although a decreased global trend in incidence was observed.