Attention-deficit hyperactivity disorder (ADHD), or hyperkinetic disorder (HKD), is a chronic neurodevelopmental disorder that begins in childhood and is characterised by a persistent pattern of inattention and/or hyperactivity-impulsivity beyond the range of developmental norms, which may impact on personal, academic, familial and societal functioning.1,2
ADHD is a diverse disorder with complex epidemiology. The prevalence rates in children, adolescents and adults can vary depending on a number of factors such as:
Could there be something else?
The diagnosis of ADHD in adults is not always straightforward and is often present alongside comorbidities which may cloud the diagnosis.1,11,12
So how do people get to the right answer?
The neurobiological component of ADHD has received much attention in recent years. Evidence exists for the association between ADHD and possible structural,20-27 functional28-33 and neurotransmitter34-39 alterations in various regions of the brain in children, adolescents and adults with ADHD.
The chronic nature of ADHD means that this disorder can have a significant impact at school40,41 and in the workplace,42-45 including an impact on relationships.42,43,46 As a consequence, the quality of life of individuals with ADHD, and the people around them, can be impaired.40,47-50 ADHD can also be associated with substantial financial burden for individuals, families and societal healthcare services.43,46,51-53
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. 2013.
- World Health Organization. The ICD-10 Classification of Mental and Behavioural Disorders. Available at: www.who.int/entity/classifications/icd/en/bluebook.pdf. Last updated 1993; 1: 1-263. Accessed 04 January 2017.
- Polanczyk G, de Lima MS, Horta BL, et al. The worldwide prevalence of ADHD: a systematic review and metaregression analysis. Am J Psychiatry 2007; 164: 942-948.
- Willcutt EG. The prevalence of DSM-IV attention-deficit/hyperactivity disorder: a meta-analytic review. Neurotherapeutics 2012; 9: 490-499.
- Fayyad J, De Graaf R, Kessler R, et al. Cross-national prevalence and correlates of adult attention-deficit hyperactivity disorder. Br J Psychiatry 2007; 190: 402-409.
- Wichstrøm L, Berg-Nielsen TS, Angold A, et al. Prevalence of psychiatric disorders in preschoolers. J Child Psychol Psychiatry 2012; 53: 695-705.
- Novik TS, Hervas A, Ralston SJ, et al. Influence of gender on attention-deficit/hyperactivity disorder in Europe–ADORE. Eur Child Adolesc Psychiatry 2006; 15(Suppl 1): I/15-I/24.
- Steinhausen HC, Novik TS. ADORE Study Group. Co-existing psychiatric problems in ADHD in the ADORE cohort. Eur Child Adolesc Psychiatry 2006; 15: I/25-I/29.
- Kessler RC, Adler L, Barkley R, et al. The prevalence and correlates of adult ADHD in the United States: results from the National Comorbidity Survey Replication. Am J Psychiatry 2006; 163: 716-723.
- Piñeiro-Dieguez B, Balanzá-Martinez V, García-García P, et al. Psychiatric comorbidity at the time of diagnosis in adults with ADHD: the CAT study. J Atten Disord 2014; J Atten Disord 2016; 20: 1066-1075.
- Brookes KJ, Mill J, Guindalini C, et al. A common haplotype of the dopamine transporter gene associated with attention-deficit/hyperactivity disorder and interacting with maternal use of alcohol during pregnancy. Arch Gen Psychiatry 2006; 63: 74-81.
- Grizenko N, Fortier ME, Zadorozny C, et al. Maternal Stress during Pregnancy, ADHD Symptomatology in Children and Genotype: Gene-Environment Interaction. J Can Acad Child Adolesc Psychiatry 2012; 21: 9-15.
- Kahn RS, Khoury J, Nichols WC, et al. Role of dopamine transporter genotype and maternal prenatal smoking in childhood hyperactive-impulsive, inattentive, and oppositional behaviors. J Pediatr 2003; 143: 104-110.
- Neuman RJ, Lobos E, Reich W, et al. Prenatal smoking exposure and dopaminergic genotypes interact to cause a severe ADHD subtype. Biol Psychiatry 2007; 61: 1320-1328.
- Martel MM, Nikolas M, Jernigan K, et al. The dopamine receptor D4 gene (DRD4) moderates family environmental effects on ADHD. J Abnorm Child Psychol 2011; 39: 1-10.
- Nikolas M, Friderici K, Waldman I, et al. Gene x environment interactions for ADHD: synergistic effect of 5HTTLPR genotype and youth appraisals of inter-parental conflict. Behav Brain Funct 2010; 6: 23.
- Retz W, Freitag CM, Retz-Junginger P, et al. A functional serotonin transporter promoter gene polymorphism increases ADHD symptoms in delinquents: interaction with adverse childhood environment. Psychiatry Res 2008; 158: 123-131.
- Nakao T, Radua J, Rubia K, et al. Gray matter volume abnormalities in ADHD: voxel-based meta-analysis exploring the effects of age and stimulant medication. Am J Psychiatry 2011; 168: 1154-1163.
- Ellison-Wright I, Ellison-Wright Z, Bullmore E. Structural brain change in Attention Deficit Hyperactivity Disorder identified by meta-analysis. BMC Psychiatry 2008; 8: 51.
- Davenport ND, Karatekin C, White T, et al. Differential fractional anisotropy abnormalities in adolescents with ADHD or schizophrenia. Psychiatry Res 2010; 181: 193-198.
- Valera EM, Faraone S, Murray KE, et al. Meta-analysis of structural imaging findings in attention-deficit/hyperactivity disorder. Biol Psychiatry 2007; 61: 1361-1369.
- Ivanov I, Bansal R, Hao X, et al. Morphological abnormalities of the thalamus in youths with attention deficit hyperactivity disorder. Am J Psychiatry 2010; 167: 397-408.
- Shaw P, Lerch J, Greenstein D, et al. Longitudinal mapping of cortical thickness and clinical outcome in children and adolescents with attention-deficit/hyperactivity disorder. Arch Gen Psychiatry 2006; 63: 540-549.
- Shaw P, Eckstrand K, Sharp W, et al. Attention-deficit/hyperactivity disorder is characterized by a delay in cortical maturation. Proc Natl Acad Sci U S A 2007; 104: 19649-19654.
- Shaw P, Malek M, Watson B, et al. Development of cortical surface area and gyrification in attention-deficit/hyperactivity disorder. Biol Psychiatry 2012; 72: 191-197.
- Purper-Ouakil D, Ramoz N, Lepagnol-Bestel AM, et al. Neurobiology of attention deficit/hyperactivity disorder. Pediatr Res 2011; 69: 69R-76R.
- Cortese S, Kelly C, Chabernaud C, et al. Toward systems neuroscience of ADHD: a meta-analysis of 55 fMRI studies. Am J Psychiatry 2012; 169: 1038-1055.
- Dickstein SG, Bannon K, Castellanos FX, et al. The neural correlates of attention deficit hyperactivity disorder: an ALE meta-analysis. J Child Psychol Psychiatry 2006; 47: 1051-1062.
- Cubillo A, Halari R, Giampietro V, et al. Fronto-striatal underactivation during interference inhibition and attention allocation in grown up children with attention deficit/hyperactivity disorder and persistent symptoms. Psychiatry Res 2011; 193: 17-27.
- Peterson BS, Potenza MN, Wang Z, et al. An FMRI study of the effects of psychostimulants on default-mode processing during Stroop task performance in youths with ADHD. Am J Psychiatry 2009; 166: 1286-1294.
- Liddle EB, Hollis C, Batty MJ, et al. Task-related default mode network modulation and inhibitory control in ADHD: effects of motivation and methylphenidate. J Child Psychol Psychiatry 2011; 52: 761-771.
- Volkow ND, Wang GJ, Newcorn J, et al. Brain dopamine transporter levels in treatment and drug naive adults with ADHD. Neuroimage 2007; 34: 1182-1190.
- Volkow ND, Wang GJ, Newcorn J, et al. Depressed dopamine activity in caudate and preliminary evidence of limbic involvement in adults with attention-deficit/hyperactivity disorder. Arch Gen Psychiatry 2007; 64: 932-940.
- Volkow ND, Wang GJ, Kollins SH, et al. Evaluating dopamine reward pathway in ADHD: clinical implications. JAMA 2009; 302: 1084-1091.
- Tomasi D, Volkow ND. Functional connectivity of substantia nigra and ventral tegmental area: maturation during adolescence and effects of ADHD. Cereb Cortex 2014; 24: 935-944.
- Economidou D, Theobald DE, Robbins TW, et al. Norepinephrine and dopamine modulate impulsivity on the five-choice serial reaction time task through opponent actions in the shell and core sub-regions of the nucleus accumbens. Neuropsychopharmacology 2012; 37: 2057-2066.
- Liu YP, Lin YL, Chuang CH, et al. Alpha adrenergic modulation on effects of norepinephrine transporter inhibitor reboxetine in five-choice serial reaction time task. J Biomed Sci 2009; 16: 72.
- Caci H, Doepfner M, Asherson P, et al. Daily life impairments associated with self-reported childhood/adolescent attention-deficit/hyperactivity disorder and experiences of diagnosis and treatment: results from the European Lifetime Impairment Survey. Eur Psychiatry 2014; 29: 316-323.
- Holmberg K, Bölte S. Do symptoms of ADHD at ages 7 and 10 predict academic outcome at age 16 in the general population? J Atten Disord 2014; 18: 635-645.
- Biederman J, Faraone SV, Spencer TJ, et al. Functional impairments in adults with self-reports of diagnosed ADHD: a controlled study of 1001 adults in the community. J Clin Psychiatry 2006; 67: 524-540.
- Brod M, Pohlman B, Lasser R, et al. Comparison of the burden of illness for adults with ADHD across seven countries: a qualitative study. Health Qual Life Outcomes 2012; 10: 47.
- de Graaf R, Kessler RC, Fayyad J, et al. The prevalence and effects of adult attention-deficit/hyperactivity disorder (ADHD) on the performance of workers: results from the WHO World Mental Health Survey Initiative. Occup Environ Med 2008; 65: 835-842.
- Adamou M, Arif M, Asherson P, et al. Occupational issues of adults with ADHD. BMC Psychiatry 2013; 13: 59.
- Pitts M, Mangle L, Asherson P. Impairments, diagnosis and treatments associated with attention-deficit/hyperactivity disorder (ADHD) in UK adults: results from the lifetime impairment survey. Arch Psychiatr Nurs 2015; 29: 56-63.
- Cussen A, Sciberras E, Ukoumunne OC, et al. Relationship between symptoms of attention-deficit/hyperactivity disorder and family functioning: a community-based study. Eur J Pediatr 2012; 171: 271-280.
- Grenwald-Mayes G. Relationship between current quality of life and family of origin dynamics for college students with attention-deficit/hyperactivity disorder. J Atten Disord 2002; 5: 211-222.
- Gudjonsson GH, Sigurdsson JF, Eyjolfsdottir GA, et al. The relationship between satisfaction with life, ADHD symptoms, and associated problems among university students. J Atten Disord 2009; 12: 507-515.
- O’Callaghan P, Sharma D. Severity of symptoms and quality of life in medical students with ADHD. J Atten Disord 2014; 18: 654-658.
- Biederman J, Faraone SV. The effects of attention-deficit/hyperactivity disorder on employment and household income. MedGenMed 2006; 8: 12.
- Hodgkins P, Montejano L, Sasane R, et al. Risk of injury associated with attention-deficit/hyperactivity disorder in adults enrolled in employer-sponsored health plans: a retrospective analysis. Prim Care Companion CNS Disord 2011; 13.
- Flood E, Gajria K, Sikirica V, et al. The Caregiver Perspective on Paediatric ADHD (CAPPA) survey: Understanding sociodemographic and clinical characteristics, treatment use and impact of ADHD in Europe. J Affect Disord 2016; 200: 222-234.