evidence: Incidence peaked at age 5–9 years, and prevalence and DALYs at age 10–14 years. Our re-analysis of data prior to 2013 showed a prevalence in children/adolescents two-fold higher (5.41%, 95% CI: 4.67–6.15%) compared to the corresponding GBD estimated prevalence (2.68%, 1.83–3.72%), with no significant differences between low- and middle- and high-income countries. We also found meta-analytic evidence of significantly increased ADHD-related mortality due to unnatural causes. While it provides the most detailed evidence on temporal trends, as well as on geographic and sex variations in incidence, prevalence, and burden of ADHD, the GBD may have underestimated the ADHD prevalence and burden. Given the influence of the GBD on research and policies, methodological issues should be addressed in its future editions. [...] DysCo Lab, Department of Psychology, Université Paris Nanterre, Nanterre, France