Services research and outcomesEpidemiology of attention-deficit/hyperactivity disorder across the lifespanPolanczyk, Guilherme; Rohde, Luis AugustoAuthor Information ADHD Outpatient Program, Child and Adolescent Psychiatric Division, Hospital de Clinicas de Porto Alegre, Federal University of Rio Grande do Sul, Brazil Correspondence to Professor Luis Augusto Rohde, Child and Adolescent Psychiatric Division, Hospital de Clinicas de Porto Alegre, Rua Ramiro Barcelos, 2350 Porto Alegre, RS, Brazil Tel: +5590035 003; fax: +55 51 3321 3946; e-mail: [email protected] Current Opinion in Psychiatry: July 2007 - Volume 20 - Issue 4 - p 386-392 doi: 10.1097/YCO.0b013e3281568d7a Buy Metrics Abstract Purpose of review Prevalence estimates of the attention-deficit hyperactivity disorder (ADHD) and the rate of persistence of symptoms across the lifespan are heterogeneous, raising questions about the validity of the diagnosis. This review aims to discuss potential reasons for variability in ADHD prevalence estimates and rates of symptom persistence, as well as to present ADHD prevalence rates during the lifespan. Recent findings The best available estimates of ADHD prevalence are around 5.29% for children and adolescents and 4.4% in adulthood. Estimates of ADHD prevalence and rate of symptom persistence over time seem to be highly affected by methodological characteristics of the studies. Summary The review of ADHD epidemiology highlights the need for standardizing study methodologies to make findings comparable. Even so, epidemiological cross-national data seem to support the validity of ADHD. © 2007 Lippincott Williams & Wilkins, Inc.