It is not clear how many children in the UK have attention deficit hyperactivity disorder (ADHD), but it is estimated that between one and five percent are affected by the condition. Boys are more likely to be affected than girls. Children with ADHD are often found to have additional mental health disorders or learning disabilities.
The precise causes of ADHD are unknown. Research has indicated that it is heritable, although the genes responsible have not been identified, and that children and young people diagnosed with ADHD have common neurobiological problems and deficits.
There is controversy about whether ADHD is a distinct developmental or behavioural disorder, as it does not have any biological markers or physical characteristics, but is recognised by behaviour alone. Readers interested in this debate may wish to read the paper by Furman. The rest of this briefing assumes ADHD is a clinical syndrome that satisfies particular diagnostic criteria.
ADHD is characterised by the early onset (before age seven, although diagnosis may be later) of three particular types of behaviour: hyperactivity, inattention and impulsiveness. There are three principal sub-types of ADHD:
● Predominantly inattentive
● Predominantly hyperactive
● A combination of the two above
A diagnosis of ADHD will only be considered if behavioural symptoms have been observed persistently in a child in more than one setting, e.g. at home and at school, for at least six months. Diagnosis is often difficult because other problems, such as epilepsy, autism, oppositional defiant order (ODD), conduct disorder, anxiety, depression and a range of learning difficulties, can result in similar behaviour to ADHD and/or mask symptoms.
All of the research and guidance literature stresses how diagnosis should be an extensive and thorough process, involving clinical examination and the collection and analysis of diagnostic information from as many relevant sources as possible, including parents, teachers and social workers.
Under-diagnosis of ADHD has been demonstrated to be a potential problem. The research shows that GPs are the main source of referrals to specialist services, but they may lack awareness of ADHD and can fail to diagnose the disorder. Referrals made by GPs have also been shown to rely heavily on parents’ perceptions of their children’s behaviour and its possible explanation by ADHD. However, there are also indications from the research that parents may be reluctant to seek help for their child through primary care if they feel that their child’s behaviour might be attributed to bad parenting. Parents often feel that professionals believe that ADHD has a psychological and social basis. They feel they are being blamed for their child’s disorder and find this very distressing.
Once a child has been referred to a specialist service, a diagnosis will be made by a clinical health professional, usually a child psychiatrist or consultant paediatrician. The National Institute for Health and Clinical Excellence (NICE) guideline on pharmacological treatments states that “diagnosis..should be made by a child/adolescent psychiatrist or a paediatrician with expertise in ADHD”.
If ADHD and its symptoms are not managed appropriately, there may be a detrimental effect on a child’s educational and social development and the child’s ability to interact with his or her peers may suffer. ADHD is a persistent condition. Although some of the symptoms may decrease over time, undiagnosed or untreated ADHD can lead to major social and behavioural difficulties in adulthood. Research suggests that young people and adults with ADHD have higher rates of unemployment, criminality, substance misuse and antisocial behaviour than young people and adults without ADHD. The importance of early and accurate diagnosis is therefore widely accepted.
● SCIE research briefing 7: Assessing and diagnosing attention deficit hyperactivity disorder (ADHD)
● SCIE research briefing 8: Treating attention deficit hyperactivity disorder (ADHD)