The Prevalence of ADHD in a Population-Based Sample

Abstract

Objective Few studies of ADHD prevalence have used population-based samples, multiple informants, and DSM-IV criteria. In addition, children who are asymptomatic while receiving ADHD mediction often have been misclassified. Therefore, we conducted a population-based study to estimate the prevalence of ADHD in elementary school children using DSM-IV critera. Methods We screened 7587 children for ADHD. Teachers of 81% of the children completed a DSM-IV checklist. We then interviewed parents using a structured interview (DISC). Of these, 72% participated. Parent and teacher ratings were combined to determine ADHD status. We also estimated the proportion of cases attributable to other conditions. Results Overall, 15.5% of our sample (95% confidence interval (C.I.) 14.6%-16.4%) met DSM-IV-TR criteria for ADHD. Over 40% of cases reported no previous diagnosis. With additional information, other conditions explained about 9% of cases. Conclusions The prevalence of ADHD in this population-based sample was higher than the 3-7% commonly reported. To compare study results, the methods used to implement the DSM criteria need to be standardized.

Prevalence of attention-deficit/hyperactivity disorder in Northern Cyprus

“…31 Although no similar studies have been reported from the TRNC to date, our methodology and results are in close agreement with studies of Turkish children from Turkey, such as the epidemiological study reported by Ercan et al 30 from the İzmir province of Turkey, which used a very similar method-logy and reported a prevalence of 13.6%. Two other epidemiological studies, one by Ercan et al 21 another by Rowland et al 9 reported highly similar results to ours, 12.7% and 12.9% respecttively. In Chilean children aged 4-18 years the prevalence of ADHD was found to be 10.4%.…”

“…We found that the percentage of children meeting ADHD diagnostic criteria was 12.8%. Although this rate is markedly higher than the 5.9% reported by a worldwide meta-analysis of ADHD prevalence, 14 it is within the range that has been reported for ADHD prevalence 9 as well as that of epidemiological studies conducted in Turkey, 21,30 and Chile. 31 Although no similar studies have been reported from the TRNC to date, our methodology and results are in close agreement with studies of Turkish children from Turkey, such as the epidemiological study reported by Ercan et al 30 from the İzmir province of Turkey, which used a very similar method-logy and reported a prevalence of 13.6%.…”

“…The second most common type was the inattentive type with a rate of 33.3% (n=24), and the least common type was the hyperactive type (5.6%, n=4). A recent metaanalysis 25 pointed out that the most commonly seen subtype of ADHD is the combined type, as was also found in studies from North Carolina, 9 Colombia, 12 Brazil, 38,39 Italy, 8 Majorca, 11 Venezuela, 15 Texas, 13 Saudi Arabia, 10 Lebanon, 40 and Turkey. 21 Conversely, ADHD prevalence studies from Nigeria 41,42 and a prevalence study from Brazil 43 reported that the inattentive type was the most common subtype.…”

“…31 A review of the worldwide epidemiological studies on ADHD prevalence revealed a wide range of prevalence's, ranging from 0.9% to 20%. [8][9][10][11][12][13][14][15][16][17] Some studies have attributed the wide variation in ADHD prevalence to cultural and geographical factors, while many others have advocated that these discrepancies result from the diagnostic systems and methodology used, sources of information, and whether the diagnostic criteria (impairment and involving at least two domains) are required. 14 We used strict DSM-IV-TR diagnostic criteria for ADHD of symptoms being observed in at least two environments, a symptom onset before the age of 7 years, and a minimum symptom duration of 6 months.…”

“…[8][9][10][11][12][13][14][15][16][17] The prevalence of ADHD is lower in European countries compared with North America. 18 Thus, emphasis has been laid on cultural differences as a potential cause of the variation in ADHD prevalence.…”