Need to know
Dr Clodagh Murphy and Professor Eric Taylor tackle questions raised by GP Dr Neil Statham
1. What are the diagnostic features of attention deficit hyperactivity disorder (ADHD)?
ADHD is a common childhood neurobehavioural disorder. Core features are impulsivity, inattention and hyperactivity, and should be diagnosed using DSM-IV diagnostic criteria. ADHD can result in significant academic underachievement, behavioural problems, difficulties with family and friends, recklessness and low self-esteem.
ADHD has three diagnostic subtypes: predominantly inattentive, predominantly hyperactive and the two combined. Hyperkinetic disorder (HKD) is a more stringent diagnosis and is made using ICD-10 diagnostic criteria. A diagnosis of HKD requires the presence of at least six specific symptoms of inattention, three of hyperactivity and one of impulsivity. HKD symptoms are pervasive; they occur across settings, such as home
and school. Both diagnoses are used meaningfully in the UK.
By definition, symptoms of ADHD must present before seven years of age. In reality, symptoms often present in early childhood, and can be noticed before the age of two.
ADHD can co-occur with other psychiatric disorders: tics, Tourette's, epilepsy, learning disability, conduct disorder, oppositional defiant disorder, depression and anxiety. It is now recognised that symptoms of ADHD
frequently persist into adulthood, and untreated adult ADHD can cause significant impairment both at work and home.
2. Is the aetiology known?
The precise cause is unknown. However, ADHD is a complex heterogeneous disorder, and an individual's vulnerability to ADHD may be influenced by genetic, neuropsychological and social variables. First-degree relatives of people with ADHD have a three to five times greater risk of the condition.
Structural and functional brain imaging studies have identified subtle abnormalities in frontal and temporal regions, basal ganglia and cerebellum. Structural abnormalities are non-progressive, have been noted in early development and are not secondary
to treatment with stimulants. Functional imaging is suggestive of altered prefrontal dopamine activity and increased dopamine binding capacity. Neuropsychological studies have noted differences in higher-order cognitive functions and motivation.
ADHD has also been associated with environmental risks: low birth weight, prenatal exposure to benzodiazepines/alcohol/nicotine, obstetric complications and severe
early deprivation. The type of home/school relationship can act as maintaining or protective variables.
3. What is the prevalence?
The prevalence of ADHD varies across cultures, and depends in part on the diagnostic criteria used (HKD in ICD-10 vs ADHD in DSM -IV). ADHD has a wider diagnostic net than HKD. Approximately 3 to 5 per cent of children and adolescents would meet DSM-IV diagnostic criteria for ADHD. However, not all of these children would require medication. About 1 per cent of the same population would meet ICD-10 criteria for HKD.
As with other neurodevelopmental disorders, males are more commonly affected, with a 3:1 male to female ratio.
4. How can a straightforward behavioural problem be distinguished from ADHD?
Young children can be boisterous, restless, disobedient and impulsive. But this behaviour may vary across carers, home and school, and may readily reduce with simple parenting strategies – this does not imply ADHD.
Children with ADHD have pervasive and consistent problems with impulsivity, inattention and over-activity. In contrast to others of the same age, they may be more restless, loud, easily distracted and unable to sit or play quietly. Such problems persist in both structured and unstructured settings: in either a quiet classroom or workplace, or in a playground or party. People with ADHD may be constantly on the go, sleep less than their peers, be unable to complete tasks and may feel a sense of restlessness.
Ironically, children may not present with symptoms when in a clinical setting that is novel and free of the usual requirements of home and school. Clinical presentation can vary from concerned parents, school reports of an inability to remain seated, constant fidgeting, inattention and blurting out answers in class, to dreamy, inattentive behaviour, or a parent exhausted by their child's behaviour. Target behaviours are considered in the context where they occur, and may be diagnostic if excessive for age and IQ.
5. What are the management options?
NICE guidelines recommend that drug treatment is initiated by an ADHD specialist, following comprehensive assessment and diagnosis. Continued prescribing and monitoring of medication can be carried out by GPs, under shared care agreements.
Treatment options include medication and behavioural psychological management. Gold standard treatment combines the two approaches. Choice of treatment is based on severity of symptoms, impact of symptoms, availability of appropriate home/school resources and patient/family preferences. Behavioural interventions can be effective across home and school, and new parent/teacher behavioural management skills can be generalised to other areas of home/school life.
However, if behavioural techniques do not result in a significant improvement within a few weeks, medication should be advised. Children who meet diagnostic criteria for HKD are likely to require medication. Medication can be very effective – about 60 per cent of children will respond to a standard prescribing regime, and a further 30 per cent may require more detailed monitoring to achieve maximal dose-response. Some 10 per cent of children may require tertiary
level psychopharmacological management with second- or third-line medication.
Additional treatment of associated problems may be helpful. Social skills training can help improve relationships and communication, reducing long-term loss of friends, arguments and low self-esteem.
6. What are the indications for referral?
Patients should be referred for assessment of ADHD if concerns arise regarding inattention, impulsivity and overactivity. Patients can present in a number of ways. Parents may not have noticed problems with inattention, but the child's impulsivity, over-
activity or recklessness may result in numerous accidents, frequent presentation at A&E or multiple school exclusions. Adults may recognise their own symptoms, often following their child's assessment and diagnosis
7. What is the best management while waiting for a specialist opinion?
The first step in good primary care management includes identification of ADHD symptoms. Parent/teacher Conner's rating scales can be helpful in assessing the pervasiveness of behaviour, and impact of symptoms on the child and their family. However, these may be more easily carried out as part of a multidisciplinary assessment. Physical examination should exclude other possible causes of poor attention, such as difficulties with hearing, vision or epilepsy. If symptoms are suggestive of ADHD, you should refer the patient to your local community mental health team or developmental paediatrician for multidisciplinary assessment of ADHD.
Depending on age and functioning level of the patient, parent training in behavioural management or individual cognitive behavioural therapy (CBT) may help to reduce associated behavioural problems such as tantrums, anger and aggression. If patients are motivated to reduce use of illicit drugs and alcohol, referrals can be made to local drug and alcohol teams.
Education about ADHD can be helpful to patients, families and schools. Parents may feel blamed or responsible for ADHD, and may be grateful for information on the condition. Patients and their families may benefit from contacting Attention Deficit Disorder Information Support Services (ADDISS). It may be useful to consider application for a Statement of Special Educational Needs.
Parents, schools and patients may request medication to 'calm them down'. Benzodiazepines should be avoided in ADHD. They are not effective, can lead to behavioural disinhibition and are associated with dependency after only four weeks of regular use.
8. What monitoring is required with medication and why?
Methylphenidate (Concerta XL, Equasym, Equasym XL and Ritalin), dexamfetamine (Dexedrine) and atomoxetine (Strattera) are all recommended by NICE as first-line
medication for ADHD.
Side-effects of stimulant medication can include loss of appetite, abdominal discomfort, growth retardation, insomnia, tearfulness and tics. Hypertension and hypotension can occur; peripheral vasodilatation can result in reflex tachycardia. Methylphenidate may lower the threshold for seizures, although data is inconclusive. Compliance with medication can be helped by informing families that initial side-effects can be both transient and dose-related.
A physical examination should always be carried out before prescribing, for assessment of health and to rule out problems such as raised blood pressure, signs of liver damage, heart murmur, dysmorphic features and signs of poor care. Likewise, a medical history should include questions regarding syncope on exercise, seizures and tics. Blood pressure, pulse, head circumference, height and weight should be documented before starting medication, and monitored regularly (six-monthly) once a stable dose
level is attained. Height and weight measurements should be routinely plotted on growth charts. Blood pressure and pulse should also be monitored at each dose
Routine monitoring should include appetite, insomnia, tics, withdrawal and mood. Although pharmaceutical companies do recommend blood tests, this is not an
evidence-based practice for monitoring ADHD. Unnecessary repeat blood tests may have an adverse effect on a child's compliance with treatment.
Monitoring of dose response can help ensure a successful trial of medication. Family compliance with medication can be helped by education, optimising dose response and targeting optimal timing of medication. However, this involves consultation with home and school and may be more easily carried out by a multidisciplinary team.
Methylphenidate is a controlled substance and should be prescribed with care. However, there is no evidence that stimulant use increases the risk of substance abuse. A careful drug and alcohol history should be taken in older patients, and patients should be advised against using illicit drugs while taking methylphenidate.
Methylphenidate is prescribed with increasing frequency in adults, and care should be taken with contraindications inherent in both paediatric and adult populations. Stimulant use is contraindicated in cardiac arrhythmias, angina pectoris,
glaucoma, schizophrenia and where there
is a history of previous sensitivity. Stimulants should not be co-prescribed with monoamine-oxidase inhibitors, because of the risk of hypertensive crisis. Methyl-phenidate used in combination with
tricyclic antidepressants can result in increased tricyclic blood levels.
Methylphenidate may inhibit the metabolism of coumarin anticoagulants, phenylbutazone and the anticonvulsants phenytoin, phenobarbital and primidone, and would need dose reduction. Stimulants can be used with caution with co-morbid presentations of depression, epilepsy, hypertension, tics and pervasive developmental disorders, but should be prescribed and monitored by
Atomoxetine is not a stimulant medication and works instead as a selective noradrenaline reuptake inhibitor. Side-effects include raised blood pressure, stomach pain, nausea, loss of appetite, sedation, irritability and mood swings. Patients should be monitored for seizures and suicidal ideation. There have been reports of QT interval prolongation. ECG monitoring is recommended for those at risk of a long QT interval – via
either family history or prescription of medication that can cause QT prolongation or electrolyte imbalance.
9. What actions would have to be taken if any abnormalities were detected during monitoring?
While evidence supporting long-term growth retardation is inconclusive, many families choose to have drug-free periods. Some may choose to take medication only on school days or during term-time. The
ability to have drug-free periods will depend in part on symptom severity, and the ability of the family to manage behaviour in a
calm, consistent, positive manner. Methyl-phenidate is a short-acting drug and can be safely stopped immediately to allow drug-free periods. Any adverse drug reactions should be reported using the Yellow Card system.
Appetite suppression typically occurs
during the day following daytime doses of medication and wears off in the evening.
Patients may well graze for food in the evening, and healthy snacks such as fruit should be made available. If domestic and school timetables allow, delaying morning medication until after breakfast may help.
Atomoxetine should be discontinued in patients with symptoms suggesting impaired liver function, such as jaundice or dark urine. Use of blood tests
to monitor liver function is not effective.
10. At what age should methylphenidate be stopped?
Trials of long-term use of methylphenidate are limited. Treatment is based on clinical need and may continue for a number of years. Methylphenidate may be stopped once a year to evaluate progress. This should be done with careful discussion with the child and their family, and care should be taken to avoid stopping medication at inopportune times, such as during examinations or when starting new jobs. The transfer of care from child to adult services varies across local agencies from 16 to 18 years of age. Transition to adult ADHD services is an important stage and should be carefully planned to ensure continuity of care.
Clodagh Murphy is a specialist registrar in child and adolescent psychiatry at South London and Maudsley NHS trust and a clinical research worker in the department of brain maturation at the Institute of Psychiatry, King's College London.
Eric Taylor is head of the department of child
and adolescent psychiatry at the Institute of Psychiatry and an honorary consultant in child neuropsychiatry at the South London and Maudsley NHS Trust.
What i will do now
Dr Neil Statham responds to the answers to his questions
• The distinction between ADHD and HKD is now clear and I was unaware of the family connection.
• The stated prevalence means we are probably under-diagnosing it in practice. Distinguishing behavioural difficulties from ADHD/HKD is at times problematic – especially when we are faced with a distressed non-coping parent. But contacting the school or nursery can provide useful additional information to help with a rational judgment on when to refer.
• I was unaware of ADDIS and I will add this to my list of self-help groups.
Neil Statham is a GP in Newport, Gwent
• ADHD affects 3-5 per cent of children. It comprises impulsivity, inattention and hyperactivity, and should be diagnosed using DSM-IV criteria
• Hyperkinetic disorder is a more stringent diagnosis
• Symptoms are often noticed before the age of two but must be present before seven
• A first-degree relative with ADHD greatly increases risk
• Brain imaging has identified subtle abnormalities in frontal and temporal regions, basal ganglia and cerebellum
• 60 per cent of children who need medication will respond to a standard prescribing regime
• Evidence of long-term growth retardation is inconclusive
• Methylphenidate should be stopped once a year to evaluate progress