Section 1 Epidemiology and aetiology
Attention deficit hyperactivity disorder (ADHD) is a behavioural syndrome characterised by core symptoms of hyperactivity, impulsivity and inattention. Some patients diagnosed with ADHD are predominantly hyperactive and impulsive, while others are chiefly inattentive.
The proportion of children in the UK reported as having been diagnosed with ADHD is 1-5%. ADHD is diagnosed more frequently in boys than in girls. However, reviews of the literature suggest studies indicating a male:female ratio of more than 3:1 should be treated with caution.
Children with ADHD are often found to have one or more other mental health disorders or learning disabilities.
ADHD lacks biological markers or physical characteristics, so it is recognised by behavioural characteristics. ADHD is generally accepted as a robust clinical syndrome that satisfies particular diagnostic criteria.
The precise causes of ADHD are unknown. Research has indicated that ADHD is 'highly heritable',1 but the responsible genes have not been identified.
Research has also demonstrated that children and young people diagnosed with ADHD have common neurobiological problems and deficits.
ADHD affects the brain, making it difficult for children to control their behaviour. Poorly controlled ADHD can have a calamitous effect on the lives of the patient, their family and friends.
Years of being told off or hectored for bad behaviour can lead to educational underachievement and frank social disadvantage.
The line between normal and abnormal behaviour is often blurred and subjective. Many children who have other emotional or behavioural disturbances also show signs of core ADHD symptoms.
ADHD is related to the frontal lobe of the brain working more slowly, research suggests.2 This may be because children with ADHD have a shortage of certain neurotransmitters, believed to be dopamine and noradrenaline. This deficit means the frontal lobe cannot react and respond to information appropriately.
Section 2 Making the diagnosis
Two main diagnostic criteria are in use, ICD-10 and DSM-V. ICD-10 uses a narrower diagnostic category, which includes people with more severe symptoms and impairment. DSM-V has a broader, more inclusive definition, which includes a number of ADHD subtypes.
Definitive diagnosis requires the presence of inattention, impulsivity and hyperactivity before the age of seven, and that symptoms continue for at least six months, occur in more than one setting, cause significant functional impairment and cannot be better explained by another psychiatric childhood condition.
First suggestions of ADHD are typically educational underachievement, but can involve road accidents, minor criminality and serious yet not readily explicable disruptions to family life. For a child with ADHD, the outside world rushes in as a flood of noise and images, making it difficult for them to decide what is important.
ADHD differs from naughty or boisterous behaviour in that these children struggle with inattention, often daydream, are disorganised and often lose things. Children with hyperactivity problems seem to be on the go all the time and are often restless and talkative.
Many children show disruptive behaviour as part of growing up, but those with ADHD have behavioural problems so all-encompassing and unrelenting, they disrupt their lives and the lives of those around them.
It has been suggested ADHD is overdiagnosed and overtreated and that many of these children are simply naughty or boisterous. Research shows this is not the case in general.3 Clinicians do not overdiagnose attention problems and are not biased to label 'disadvantaged' children with attention problems.4
A key consideration in differentiating naughty or boisterous behaviour from the core symptoms of ADHD is the degree of functional impairment across multiple contexts and the degree to which these deficits interfere with a child's normal developmental trajectory, as perceived by multiple informants.
Important differential diagnoses include:
- Learning disabilities
- Pervasive developmental disorder
- Oppositional defiant disorder
- Conduct disorder
- Psychotic disorders
- Anxiety disorders
|Questions GPs can ask if ADHD is suspected|
Section 3 Managing the condition
Medication helps many children with ADHD, but about one in five will gain no benefit.
Other children who do benefit find the side-effects unpleasant, to the point that they discontinue their medication.
Pharmaceutical treatment should be started by a specialist child and adolescent psychiatrist or paediatrician who has been trained in this field.
Types of intervention
Combination treatment of behavioural interventions and medication management, and medication management alone, are significantly superior to intensive behavioural treatment alone and to routine community care in reducing the symptoms of ADHD.
In other areas of functioning (anxiety symptoms, academic performance, parent/child relations and social skills), combination treatment is consistently superior to routine community care, whereas medication alone or behavioural treatment alone are not.4
Stimulant drugs act by increasing the amount of dopamine or noradrenaline in the brain. Commonly used stimulants include methylphenidate, dexamfetamine and mixed salts of amphetamine.
Stimulant medication can improve attention span, decrease distractibility, increase ability to finish tasks, decrease hyperactivity and reduce impulsivity.
The different formulations of stimulant drugs differ mostly in duration of action. Short-acting stimulants last three to five hours. Longer-acting ones last up to 18 hours.
A well-conducted systematic review found methylphenidate, compared with placebo, may be more effective at reducing core symptoms of ADHD in children aged five to 18 years.5
Stimulants can cause unpredictable effects, including motor tics, which transiently occur in 15-30% of children taking stimulants.
The same systematic review indicated that, compared with placebo, dexamfetamine may be more effective at controlling hyperactivity and other core symptoms of ADHD.5
Atomoxetine was originally developed as an antidepressant, but was later found to be helpful for patients with ADHD.6
Psychological treatments for ADHD can be broadly classified into behavioural, cognitive or cognitive-behavioural, and neurofeedback training.
Behavioural interventions involve teaching parents the principles of social learning, reinforcement and stimulus controlled behaviour.
Cognitive-behavioural interventions for ADHD involve teaching self-instruction, problem-solving, self-reinforcement and self-redirection.
Cognitive training studies have also attempted to target working memory and attention deficits.
Section 4 Prognosis
ADHD has traditionally been viewed as a disorder of childhood that patients will grow out of.
However, research suggests that 30-60% of those with ADHD continue to exhibit significant difficulties as adults.7
Most researchers now agree that while the core deficits underlying ADHD are lifelong, its particular presentation changes as children mature into adulthood.
By adulthood, the hyperactivity may have eased; however, the effects of ADHD on social and academic functioning and self-esteem can become cumulative7 - adults with ADHD have more marital and employment difficulties, and more driving violations. Untreated ADHD is associated with higher rates of alcohol and drug use in adulthood.7
Section 5 Case study
Luke, aged eight, is taken to see his GP because he has been in trouble at school. His mother is called to the school three or four times a week for incidents of fighting, kicking and running in corridors.
He annoys his classmates but can finish his work with one-to-one attention from a student teacher.
At home, Luke seems unable to sit still for long, has had several falls when climbing trees and needs endless prompts to tidy his toys.
His father is said to have been a 'lively' child, then a 'bright underachiever' who occasionally fell foul of the law.
On examination, Luke ran and jumped about, making noises. He swung on a chair and took the batteries out of an ophthalmoscope.
His mother was asked to list the behaviours that most concerned her.8 She was encouraged to accept others, such as making noises or climbing, as part of Luke's development as long as he remains safe.8
When Luke fights, kicks others or takes risks such as running into the road, he is given 'time out', which isolates him for a short time and allows him and his parents or teacher to calm down.
To reduce his aggression and impulsivity, Luke is taught to respond verbally rather than physically and to channel his energy into activities such as sports or music.
Over time, Luke's parents became skilled at picking their battles. Home is more harmonious. They fenced their garden, fitted a childproof gate and cut some branches off a tree, preventing him from climbing it.
His parents remain concerned about Luke's use of bad language. They have been encouraged to allow verbal responses unacceptable in other children, as this is preferable to physical aggression.
At school, Luke is less aggressive, has a statement of special educational need and now works well with a classroom assistant. He has been moved to the front of the class, where the teacher can keep an eye on him, and given one task at a time.9 He is given special tasks, like taking the register to the school office, so he can leave class without being expected to sit still for long periods.
Section 6 Evidence base
- The MTA Cooperative Group. A 14-month randomized clinical trial of treatment strategies for attention-deficit/hyperactivity disorder. Arch Gen Psychiatr 1999; 56: 1073-86.
The Multimodal Treatment of ADHD (MTA) study looked at how intensive pharmaceutical treatment compared with intensive behavioural therapy, or a combination of the two, for a period of up to 14 months.
Combination treatment and medication management alone were both significantly superior to intensive behavioural treatment alone and to routine community care in reducing ADHD symptoms. The study also showed that these benefits last for as long as 14 months.
In other areas of functioning, such as anxiety, academic performance and social skills, combination treatment was consistently superior to routine community care, whereas medication alone or behavioural treatment alone were not.
- Rutter M, Bishop D, Pine D et al. Rutter's Child and Adolescent Psychiatry. Oxford, Wiley, 2001.
Chapter 25, Syndromes of Hyperactivity and Attention Deficit, is the definitive overview of assessment, diagnosis, interventions and information to give parents and teachers.
- ADHD foundation. Regularly updated information on guidelines, general management information and templates.
- ADHD training package for GPs, sponsored by the Welsh Assembly. www.adhdtraining.co.uk
Contributed by Dr Sabina Dosani, consultant child and adolescent psychiatrist at the Leapfrog Clinic, Harley Street, central London.
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1. Bauermeister JJ, Shrout PE, Chavez L et al. J Child Psychol Psychiatr 2007; 48: 831-9.
2. Chronis AM, Jones HA, Raggi VL. Clin Psychol Rev 2006; 26: 486-502.
3. Vitiello B. J Child Adolesc Psychopharmacol 2005; 15: 10-11.
4. The MTA Cooperative Group. Arch Gen Psychiatr 1999; 56: 1073-86.
5. King S, Griffin S, Hodges Z et al. Health Technol Assess (Winchester) 2006; 10: iii-iv.
6. Gibson AP, Bettinger TL, Patel NC et al. Ann Pharmacother 2006; 40: 1134-42.
7. Harpin VA. Arch Dis Child 2005; 90 (Suppl 1): I 2-i7.
8. Barkley RA. J Clin Psychiatr 2002; 63 (Suppl 12): 36-43.
9. Christophersen ER, Mortweet SL. Treatments that work for children. Empirically supported strategies for managing childhood problems. Washington DC, APA, 2001.