What is ADHD?

Attention-deficit/hyperactivity disorder or ADHD is a neurodevelopmental disorder.1–3 An average of 2.2% (0.1–8.1%) of children and 2.8% (0.6–7.3%) of adults worldwide are affected by ADHD.4 The disorder is characterised by three core symptoms:1

  • Inattention, and/or
  • Hyperactivity, and
  • Impulsive behaviour

In children there is evidence for a difference in symptoms between girls and boys, with girls more likely to present primarily with inattentive features.1,5–7 However, ADHD is more frequently diagnosed in boys than in girls.1,5,8 It has been suggested this may be because symptom manifestations in girls tend to be less obvious than in boys9 and because girls are less likely to have co-existing disruptive behavioural disorders.6,7

Note: These are examples only. Gender differences may not be evident.

Adapted from Hoseini BL, et al. 2014.9

ADHD can be a lifelong condition

Although symptoms begin in childhood, ADHD persists into adulthood in around 40–66% of individuals.10,11 ADHD has a significant impact on quality of life,12–14 and can result in educational and occupational under-achievement, and problems with relationships.15–18

ADHD may go undiagnosed in childhood.18–20 In fact, some adults learn that they might have ADHD when their child is diagnosed.19

  1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5®). Arlington, VA: American Psychiatric Association; 2013:59–65.
  2. World Health Organization. The ICD-10 Classification of Mental and Behavioural Disorders. Available at http://www.who.int/classifications/icd/en/bluebook.pdf. Last accessed December 2018.
  3. Peasgood T, et al. Eur Child Adolesc Psychiatr. 2016;25:1217–1231.
  4. Fayyad J, et al. Atten Defic Hyperact Disord. 2017;9:47–65.
  5. Willcutt EG. Neurotherapeutics. 2012;9:490–499.
  6. Biederman J, et al. Am J Psychiatry. 2002;159:36–42.
  7. Biederman J, Faraone SV. Psychiatr Clin North Am. 2004;27:225–232.
  8. Nøvik TS, et al. Eur Child Adolesc Psychiatry. 2006;15 Suppl 1:I15–I24.
  9. Hoseini BL, et al. Int J Pediatr. 2014;2:445–452.
  10. Faraone SV, et al. Psychol Med. 2006;36:159–165.
  11. Barkley RA, et al. J Abnorm Psychol. 2002;111:279–289.
  12. Lensing MB, et al. J Atten Disord. 2015;19:405–413.
  13. Grenwald-Mayes G. J Atten Disord. 2001;5:211–222.
  14. Quintero J, et al. J Atten Disord. 2017; https://doi.org/10.1177/1087054717733046
  15. Biederman J, et al. J Clin Psychiatry. 2006;67:524–540.
  16. Able SL, et al. Psychol Med. 2007;37:97–107.
  17. de Graaf R, et al. Occup Environ Med. 2008;65:835–842.
  18. Brod M, et al. Health Qual Life Outcomes. 2012;10:47.
  19. Faraone SV, et al. Arch Intern Med. 2004;164:1221–1226.
  20. Kooij S, et al. BMC Psychiatry. 2010;10:67.