Attention-deficit hyperactivity disorder (ADHD), or hyperkinetic disorder (HKD), affects people of all ages, and ADHD prevalence rates are known to vary between children, adolescents and adults (Table).1-4
Table: Summary of ADHD prevalence rates in different age groups
|Age group||Prevalence (%)|
|Pre-school children* (Europe)||1.8–5.4%1-3|
|Children and adolescents (worldwide)||0.1–8.1% (2.2% overall)4|
|Adults (worldwide)||0.6–7.3% (2.8% overall)4|
*Aged ≤6 years
Can you describe the differences in presentation of the children and adults that attend your practice? | Dr Joel Young | Rochester Centre for Behavioral Medicine, Rochester, MI, USA
Children and adolescents
Few studies exist regarding ADHD prevalence rates in pre-school children (aged ≤6 years); however, prevalence rates in Norway, Germany and Spain have been estimated to be 1.9%,1 1.8%,2 and 5.4%,3 respectively. An epidemiological study of 20 countries from the World Health Organization World Mental Health Surveys, found that across high-, upper–middle-, and low-/lower–middle-income countries, the mean worldwide prevalence of ADHD was ~2.2% overall (range: 0.1–8.1%) in children and adolescents (aged <18 years).4 In this study, prevalence rates of ADHD in children and adolescents were highest in the USA (8.1%) and lowest in Iraq (0.1%), Poland (0.3%) and Romania (0.4%).4
Figure: Global prevalence of childhood ADHD. Figure developed using data from Fayyad J et al. Atten Defic Hyperact Disord 2017; 9: 47-65.4
ADHD was reported to persist into adulthood in an estimated 50–65% of patients.4-6
The prevalence of ADHD in adults (n=26,744) aged 18–44 years from a range of countries in Asia, Europe, the Americas and the Middle East was ~2.8% overall; the lowest prevalence was reported in Iraq (0.6%) and Romania (0.6%), and the highest was reported in France (7.3%).4
Figure: Global prevalence of adult ADHD. Figure developed using data from Fayyad J et al. Atten Defic Hyperact Disord 2017; 9: 47-65 and Ebejer JL et al. PLoS One 2012; 7: e47404.4,6
Once considered to be a childhood disorder,7 ADHD is now acknowledged to persist into adulthood in ~50–65% of patients.4-6
Predictors for persistence into adulthood over time may include severity of symptoms,8 psychosocial adversity and psychiatric comorbidities as reported in females with ADHD.9
The reported prevalence rates of ADHD vary due to population characteristics, methodological, environmental and cultural differences, and variability in identification and diagnostic guideline tools employed in studies.10
- Wichstrøm L, Berg-Nielsen TS, Angold A, et al. Prevalence of psychiatric disorders in preschoolers. J Child Psychol Psychiatry 2012; 53: 695-705.
- Schlack R, Hölling H, Kurth BM, et al. The prevalence of attention-deficit/hyperactivity disorder (ADHD) among children and adolescents in Germany. Initial results from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2007; 50: 827-835.
- Canals J, Morales-Hidakgo P, Jane M, et al. Prevalence in Spanish preschoolers: comorbidity, socio-demographic factors, and functional consequences. J Atten Disord 2016; 22: 143-153.
- Fayyad J, Sampson NA, Hwang I, et al. The descriptive epidemiology of DSM-IV Adult ADHD in the World Health Organization World Mental Health Surveys. Atten Defic Hyperact Disord 2017; 9: 47-65.
- Faraone SV, Biederman J, Mick E. The age-dependent decline of attention deficit hyperactivity disorder: a meta-analysis of follow-up studies. Psychol Med 2006; 36: 159-165.
- Ebejer JL, Medland SE, van der Werf J, et al. Attention deficit hyperactivity disorder in Australian adults: prevalence, persistence, conduct problems and disadvantage. PLoS One 2012; 7: e47404.
- Biederman J, Mick E, Faraone SV. Age-dependent decline of symptoms of attention deficit hyperactivity disorder: impact of remission definition and symptom type. Am J Psychiatry 2000; 157: 816-818.
- Lara C, Fayyad J, De Graaf R, et al. Childhood predictors of adult attention-deficit/hyperactivity disorder: results from the World Health Organization World Mental Health Survey Initiative. Biol Psychiatry 2009; 65: 46-54.
- Biederman J, Petty CR, O’Connor KB, et al. Predictors of persistence in girls with attention deficit hyperactivity disorder: results from an 11-year controlled follow-up study. Acta Psychiatr Scand 2012; 125: 147-156.
- Skounti M, Philalithis A, Galanakis E. Variations in prevalence of attention deficit hyperactivity disorder worldwide. Eur J Pediatr 2007; 166: 117-123.