Background

Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most prevalent disorders in childhood, and can lead to problems through adolescence and adulthood. The varieties of symptoms of ADHD are generally grouped under two clusters of behavioural problems: hyperactive-impulsive and inattention

ADHD is typically first diagnosed in childhood, with symptoms persisting into adolescence and adulthood. It is estimated that as many as 50% of the children seen in child psychiatry settings suffer from ADHD, whilst the disorder has an overall occurrence of 3-5% in school children.¹ ADHD is more common in males than in females and persists from early childhood through to adulthood with an estimated 15% of children with ADHD fulfilling the diagnostic criteria by the age of 25, and with a proportion as high as 65% continuing to show some symptoms of inattention.⁶ Beyond symptoms directly associated with ADHD, children diagnosed with the disorder are more likely to drop out of school, exhibit antisocial behaviour, experience unemployment, teenage pregnancy, substance abuse problems in adolescence, and have relationship and social difficulties.²

Diagnosis

Diagnosis of ADHD is usually provided by a health care professional such as a psychiatrist, psychologist or the family doctor, following a variety of assessment procedures and consultation with parents and teachers. Diagnosis is carried out according to the criteria defined in the diagnostic statistical manual of mental disorders (DSM),³ and requires children to present inattention and impulsive-hyperactive symptoms (see the following tables for examples). A diagnosis of ADHD can be made if these behaviours are often present, persistent for at least 6 months, and are judged to have produced a level of abnormal functioning inconsistent with normal development. Also other conditions potentially accounting for the emergence of symptoms of ADHD need to be excluded (e.g. anxiety, psychotic disorder). According to the DSM there are three possible types of ADHD diagnosis: a combined inattentive and hyperactivity-impulsivity type, featuring symptoms of both hyperactive-impulsivity and inattention; an inattentive type, where inattentive symptoms are dominant, and a hyperactive-impulsive type, where only the hyperactivity-impulsivity are present.

The causes of ADHD

Biological theories and, in particular, genetics, have attempted to shed light on ADHD. Research using twin studies has shown that as much as 50 – 80% of ADHD symptoms in identical twins can be attributed to shared genes.⁵ Similar results have also been found in studies examining the rate of ADHD in the immediate family of children with the disorder, and in adoption studies.⁶ Subsequent research has led to the identification of specific genes associated with ADHD and research into the causes of the disorder. However, the development of ADHD is also dependent on environmental circumstances, such as maternal smoking or drinking during pregnancy.⁷ Differences in genetics and environmental experiences may account for the differences observed between children in symptom presentation and severity. Also the existence of ADHD subtypes, as provided by diagnosis, may be reflected in the combination of environmental and genetic factors. Development environment, parenting, and education can also have a substantial impact on symptom severity and prognosis. Biological, as well as psychosocial and social factors all contribute to the course of the disorder.⁸

Symptoms

Hyperactive-impulsive symptoms of ADHD are thought to be dependent on an inhibitory deficit, as shown in a variety of behaviours. This deficit leads to a breakdown in the ability to regulate the amount of relevant information needed to achieve a goal, focus attention toward that goal, dispose of irrelevant information and limit inappropriate behaviours that may interfere with achieving that goal. Such behaviours include restlessness, talking excessively, having difficulties in maintaining a position (e.g. staying seated), interrupting other people’s activity and talking excessively and in inappropriate circumstances.

Attention is a broad and a multidimensional cognitive process that is thought to influence the accuracy of a large number of behaviours. Attention problems evident in children with ADHD include the inability to sustain attention, to persist in tasks, and in remembering and following rules and instructions, and difficulty in resisting distraction while doing so.

Cognitive problems may also be present in children with an ADHD diagnosis. Common cognitive problems in ADHD are difficulties in memory, information processing, planning and anticipation, verbal-fluency and self-monitoring. These cognitive problems play some role in effective task performance and behaviour.

Assessment, treatment and support

Assessment for ADHD involves several methods, including clinical interviews with the child and parents, academic reports, parent and teacher assessments, psychological tests of vigilance and cognitive ability, and medical examination for potential contributing medical problems.

There are a number of different treatments available for ADHD. Treatment options include medication, psychological interventions and dietary changes. Combinations of these treatments are also possible; however, the exact effectiveness of each intervention for each particular case is still difficult to estimate, due to the high variability often observed in treatment response.¹⁵

The most common medications prescribed for ADHD are stimulants; these medications work by stimulating the areas of the brain responsible for deploying attention and inhibiting impulsive behaviours. The most commonly prescribed stimulants are Methylphenidate, Amphetamines, and Dextroamphetamines, also known by their brand names as Concerta, Ritalin, Adderall and Dexadrine. Alongside or as an alternative to drug treatments, medical professionals tend to encourage psychological interventions, such as cognitive-behavioural therapy (CBT). Such psychological interventions are implemented at home and at school and typically revolve around the selective use of reward and punishment principles, in an attempt to shape children’s behaviour.⁹

Dietary interventions that suggest eliminating artificial colours, flavourings and some preservatives from food have also been advocated.¹⁰

As with assessment and treatment, support for children with ADHD and their families is multi-professional, including GPs, educators, childminders and more specialised health care professionals such as psychiatrists, psychologists and medical consultants. There are also a large number of websites and charities dedicated to providing information and support for families of a child diagnosed with ADHD.

At a national level, the NICE guidelines provide an evidence-based framework for medical professionals working with children and adults with ADHD.¹¹

Examples of psychological/behavioural strategies

Conclusion

ADHD is a one of the most prevalent and complex developmental disorders. It is made up of a number of symptoms encompassing hyperactivity-impulsivity and attention problems and presentation can vary from child-to-child. Currently one of the leading theories regarding the cause of ADHD is based on genetics but it is not yet fully understood which components of the disorder are due to genes and which are due to the effect of the environment. At the current stage the cause of ADHD is better understood as shared between biological and environmental factors.

However, the current understanding of ADHD has provided effective treatment strategies as outlined by the NICE guidelines.¹¹ These guidelines suggest a case-by-case approach and emphasise that assessment and treatment should be carried out in accordance with the child’s specific difficulties. Such treatments often benefit from a mixed-method approach that combines medication with psychological interventions.

Although ADHD has been historically a widely and well-researched disorder, further advancements in this area are still needed. In particular, promising findings can be expected from the fields of genetic and neuroscience research that would help define the biological basis of ADHD, and from interventionbased research that will help improve the quality of existing treatments.

References

1. Goldman, L.S., et al., (1998) Diagnosis and treatment of attention-deficit/hyperactivity disorder in children and adolescents. Council on Scientific Affairs, American Medical Association. JAMA, 279(14): p.1100-7.
2. Harpin, V.A., (2005)The effect of ADHD on the life of an individual, their family, and community from preschool to adult life. Arch Dis Child, 90 Suppl 1: p. i2-7.
3. APA, A.P.A. (2000) Diagnostic and Statistical Manual of Mental Disorders: Text Revision. 4th edn ed., Washington, DC: American Psychiatric Association.
4. Mannuzza, S., Klein, R.G. (2000) Long-term prognosis in attention-deficit/hyperactivity disorder. Child Adolesc Psychiatr Clin N Am, 9(3): p. 711-26.
5. Levy, F., et al., (1997) Attention-deficit hyperactivity disorder: a category or a continuum? Genetic analysis of a large-scale twin study. J Am Acad Child Adolesc Psychiatry, 36(6): p. 737-44.
6. Biederman, J., et al., (1991) Familial association between attention deficit disorder and anxiety disorders. Am J Psychiatry, 148(2): p. 251-6.
7. Knopik, V.S., et al., (2006) Maternal alcohol use disorder and offspring ADHD: disentangling genetic and environmental effects using a children-of-twins design. Psychol Med. 36(10): p. 1461-71.
8. Nigg, J. (2006) What causes ADHD? New York: Guilford press.
9. Toplak, M.E., et al., (2008) Review of cognitive, cognitive-behavioral, and neural-based interventions for Attention-Deficit/Hyperactivity Disorder (ADHD). Clin Psychol Rev, 28(5): p. 801-23.
10. Feingold, B.E. (1980) Feingold diet. Aust Fam Physician, 9(1): p. 60-1.
11. NICE, N.I.f.H.a.C.E. (2008)Attention deficit hyperactivity disorder: diagnosis and management of ADHD in children, young people and adults. National Institute for Health and Clinical Excellence. p. Clinical guideline 72.
12. Fischer, M., Barkley, R. A., Smallish, L., & Fletcher, K. (2002). Young adult follow-up of hyperactive children: self-reported psychiatric disorders, comorbidity, and the role of childhood conduct problems and teen CD. J Abnorm Child Psychol, 30(5), 463-475.
13. Szatmari, P., Offord, D. R., & Boyle, M. H. (1989a). Correlates, associated impairments and patterns of service utilization of children with attention deficit disorder: findings from the Ontario Child Health Study. J Child Psychol Psychiatry, 30(2), 205-217.
14. Szatmari, P., Offord, D. R., & Boyle, M. H. (1989b). Ontario Child Health Study: prevalence of attention deficit disorder with hyperactivity. J Child Psychol Psychiatry, 30(2), 219-230.
15. Brown, R. T., Amler, R. W., Freeman, W. S., Perrin, J. M., Stein, M. T., Feldman, H. M., et al. (2005). Treatment of attention-deficit/hyperactivity disorder: overview of the evidence. Pediatrics, 115(6), e749-757.

This information is not meant to replace the advice of any physician or qualified health professional. The information provided by Cerebra is for information purposes only and is not a substitute for medical advice or treatment for any medical condition. You should promptly seek professional medical assistance if you have concerns regarding any health issue.