ORIGINAL RESEARCH

Studying the Epidemiology of Attention-Deficit Hyperactivity Disorder: Screening Method and Pilot Results
Andrew S Rowland, PhD1, David M Umbach, PhD2, Karen E Catoe, MPH3,
Stuart Long, BS5, David Rabiner, PhD6, AJ Naftel, MD7, Debra Panke, DO8,
Richard Faulk, MD9, Dale P Sandler, PhD10

Objective:  As part of a larger epidemiologic study of risk factors for attention-deficit hyperactivity disorder (ADHD), this pilot study combined parent and teacher information to estimate ADHD prevalence among elementary school children in a North Carolina county. The methods developed for this study and the pitfalls we encountered illustrate the challenges involved in conducting population-based studies of ADHD.
Methods:  We employed 2-stage screening using DSM-IV criteria. Teachers completed behaviour-rating scales for all children. We then administered a structured telephone interview to parents of potential cases. We screened 362 of 424 (85%) children in grades 1 to 5 in 4 schools.
Results:  According to parent reports, 43 children (12%) had previously been diagnosed with ADHD by a health professional. Thirty-four children (9%) were taking ADHD medication. Forty-six children (12.7%) met study case criteria for ADHD, based on combined teacher and parent reports. Of the 46 cases, 18 (39%) had not been previously identified. Eight previously diagnosed children, however, did not meet case criteria. After we adjusted for nonresponse, the estimated prevalence was 16% (95%CI, 12% to 20%).
Conclusions:  These data suggest that the DSM-IV prevalence of ADHD has been substantially underestimated, although the true prevalence in this population may be less than the 16% estimated here. Population-based studies of ADHD are feasible and may provide important information about practice and treatment patterns in community settings, as well as a broader understanding of the etiology and life course of this common disorder.

(Can J Psychiatry 2001:46:931–940)

Key Words:  attention-deficit hyperactivity disorder, methods, epidemiology, stimulant medication, prevalence, psychiatric disorders, children


Over their lifetime, children with attention-deficit hyperactivity disorder (ADHD) are at increased risk for academic failure, behavioural problems, substance abuse, accidents, divorce, and mental disorders (1–5). There is also concern, however, about the widespread use of stimulant medication to treat children diagnosed with ADHD (6). Despite the enormous medical and emotional costs of ADHD and the controversies surrounding its treatment, knowledge about prevalence and risk factors is limited (7).

Manuscript received June 2001 and accepted October 2001.
1Senior Staff Fellow, Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina.
2Statistician, Biostatistics Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina.
3Study Manager, CODA/Westat Inc, Durham, North Carolina.
4Study Manager, CODA/Westat Inc, Durham, North Carolina.
5Programmer, CODA/Westat Inc, Durham, North Carolina.
6Senior Research Scientist, Center for Child and Family Policy, Duke University, Durham, North Carolina.
7Director, Division of Child and Adolescent Psychiatry, Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, North Carolina.
8Child Psychiatry Resident, Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, North Carolina.
9Child Psychiatry Resident, Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, North Carolina.
10Acting Branch Chief, Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina.
Address for correspondence:  Dr AS Rowland, MPH Program, Dept of Family and Community Medicine, University of New Mexico Health Sciences Center, 2400 Tucker NE, Albuquerque, NM 87131
e-mail: arowland@salud.unm.edu

For example, estimates of the sex ratio for ADHD vary widely (8), and few studies have addressed whether prevalence varies by ethnicity or social class. In part, these knowledge gaps reflect the difficulty involved in establishing a reliable case definition and screening methodology for epidemiologic studies.

The estimated prevalence of ADHD among school-age children in the US is between 3% and 5% ,according to the DSM-IV (9). The National Institutes of Health Consensus Conference on ADHD and several recent reviews provide similar estimates (7,9,10). Yet, despite being frequently quoted, the 3% to 5% prevalence estimate is poorly documented: ADHD prevalence rates vary widely, depending on the population assessed and the methodology used (11,12).

We are conducting a population-based study that involves screening all elementary children in Johnston County, North Carolina, to estimate ADHD prevalence and identify possible risk factors. To do this, we engaged the DSM-IV diagnostic criteria for ADHD, adapting them for use in a large-scale field study. Here, we describe a method for conducting epidemiologic studies of ADHD that combines information from parents and teachers and classifies children

Next