Prevalence of attention-deficit/hyperactivity disorder: a systematic review and meta-analysis.
OBJECTIVE
Overdiagnosis and underdiagnosis of attention-deficit/hyperactivity disorder (ADHD) are widely debated, fueled by variations in prevalence estimates across countries, time, and broadening diagnostic criteria. We conducted a meta-analysis to: establish a benchmark pooled prevalence for ADHD; examine whether estimates have increased with publication of different editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM); and explore the effect of study features on prevalence.


METHODS
Medline, PsycINFO, CINAHL, Embase, and Web of Science were searched for studies with point prevalence estimates of ADHD. We included studies of children that used the diagnostic criteria from DSM-III, DSM-III-R and DSM-IV in any language. Data were extracted on sampling procedure, sample characteristics, assessors, measures, and whether full or partial criteria were met.


RESULTS
The 175 eligible studies included 179 ADHD prevalence estimates with an overall pooled estimate of 7.2% (95% confidence interval: 6.7 to 7.8), and no statistically significant difference between DSM editions. In multivariable analyses, prevalence estimates for ADHD were lower when using the revised third edition of the DSM compared with the fourth edition (P = .03) and when studies were conducted in Europe compared with North America (P = .04). Few studies used population sampling with random selection. Most were from single towns or regions, thus limiting generalizability.


CONCLUSIONS
Our review provides a benchmark prevalence estimate for ADHD. If population estimates of ADHD diagnoses exceed our estimate, then overdiagnosis may have occurred for some children. If fewer, then underdiagnosis may have occurred.
Centre for Research in Evidence-Based Practice (CREBP), Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia rthomas@bond.edu.au.
Rae
R
Thomas
Centre for Research in Evidence-Based Practice (CREBP), Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia.
Sharon
S
Sanders
Centre for Research in Evidence-Based Practice (CREBP), Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia.
Jenny
J
Doust
Centre for Research in Evidence-Based Practice (CREBP), Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia.
Elaine
E
Beller
Centre for Research in Evidence-Based Practice (CREBP), Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia.
Paul
P
Glasziou
D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000453:epidemiology*; D019985:Benchmarking; D002648:Child; D002675:Child, Preschool; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005060:Europe; D005260:Female; D006801:Humans; D008297:Male; D009656:North America; D017594:Publication Bias
ADHD; attention-deficit/hyperactivity disorder; meta-analysis; prevalence; systematic review